chore(release): 0.15.2

- bump version: package.json / dsh.plugin.json / SIDEBAR_SERVICE_VERSION - README / README_EN: feature tour converted to a table (two screenshots per row, saves space); add v0.15.2 changelog (file-tree open-in-app menu #334, tab context menu #331, diff collapse by default #270, prune empty restored panes #268, hide git windows on Windows #301, untracked files inside new folders #242, toggle/drag per-frame re-render perf #315); community QR codes landed in #325
feat(editor): 文件树「在应用中打开」子菜单（外部编辑器/图钉固定/SSH 远端/自定义编辑器） (#334 )
2026-08-22 23:30:19 +08:00 · 2026-08-22 23:19:17 +08:00 · 2026-08-22 23:13:35 +08:00 · 2026-08-22 23:11:57 +08:00 · 2026-08-22 23:11:27 +08:00 · 2026-08-22 23:09:58 +08:00
48 changed files with 2818 additions and 267 deletions
@@ -176,7 +176,7 @@ interface TabDescriptor {
   * 顺序提交）。
   * v0.12.0 起增加两个插件自有扩展（详见 §5 声明式设置）：
   * `pluginToggles`（插件自有 key，持久化在 pluginSettings[id]，无需宿主 schema 字段）
-   * 与 `render`（自定义设置面板，替代行列表）。
+   * 与 `render`（自定义设置面板，追加渲染在行列表之后，与行列表共存）。
   */
  settings?: {
    toggles?: readonly {
@@ -223,7 +223,8 @@ interface TabDescriptor {
      }[]
      multi?: boolean
    }[]
-    /** 自定义设置面板（v0.12.0+）：给出时齿轮弹窗渲染它而非行列表。
+    /** 自定义设置面板（v0.12.0+）：给出时**追加**渲染在行列表（toggles /
+     *  pluginToggles）之后，与行列表共存；未声明行列表时单独渲染。
     *  props 含 store/service/prefs、本 descriptor 的 pluginSettings blob、
     *  updatePluginSetting(key, value) 与 close()。抛错会被吞掉并显示内联错误。 */
    render?: (props: {
@@ -151,69 +151,16 @@ dsh registry enable dsh-external/dsh-better-sidebar

 ## 🖼️ 特性巡礼

-> 以下均为真实界面实拍。
+> 以下均为真实界面实拍（每行两张，点击可放大）。

-### 🗂️ 文件工作台：资源管理器
-
-支持两种格式的资源管理器：内嵌在文件预览中 / 独立显示文件树。懒加载目录树、软链接按目标类型展示（目录软链接可展开、失效链接标红）、全局文件名搜索、上传文件/文件夹与拖放上传、右键菜单（在新 Tab 打开 / 在侧边打开 / 复制路径）、悬浮 `@文件` 一键引用进输入框。
-
-<div align="center"><img width="880" alt="文件资源管理器" src="https://github.com/user-attachments/assets/a410bfd2-a8ba-43e6-873e-22417756e94d" /></div>
-<div align="center"><img width="880" alt="CodeMirror 代码编辑器" src="https://github.com/user-attachments/assets/b44b488e-568c-4ee0-b96c-e9c906598a77" /></div>
-
-### 📝 Markdown · 图片 · PDF 内联预览
-
-Markdown 预览支持 **Mermaid 图表**（`securityLevel: 'strict'` 安全渲染 + 二次清洗；点击图表弹窗放大、滚轮缩放、拖拽平移）；图片 / PDF 走媒体路由内联展示；Office 三件套由生态插件补齐。
-
-<div align="center"><img width="880" alt="Markdown + Mermaid 预览" src="https://github.com/user-attachments/assets/fe0e5182-55bb-45cc-b98b-a2877c2bdd38" /></div>
-<div align="center"><img width="880" alt="图片内联预览" src="https://github.com/user-attachments/assets/f9a58c30-5b7a-48b5-9e22-37d7e071f593" /></div>
-
-### 💻 真实终端
-
-xterm.js + node-pty 真实 shell（不是模拟器）：断线重连 transcript 回放、shell / shellArgs 可配置（设置页或 `cordis.patch.yml`）、可选为模型注入 `terminal_*` 工具（agent 可直接开终端跑命令）。
-
-<div align="center"><img width="880" alt="真实终端" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div>
-
-### 🌿 Git 面板
-
-暂存 / 取消暂存 / 提交（`Ctrl+Enter`）/ 还原，历史列表；点击改动文件打开 **VSCode 式 diff tab**（红绿行级对比）。
-
-<div align="center"><img width="880" alt="Git 面板" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div>
-
-### 🌐 内嵌浏览器
-
-多开网页 tab：后退 / 前进 / 刷新 / 地址栏；内容运行在**不透明源沙箱 iframe**（界面实时显示沙箱状态，可按页面临时解锁）；聊天里的外链点击可被接管到侧边栏打开（按协议分流，可配）。
-
-<div align="center"><img width="880" alt="内嵌浏览器" src="https://github.com/user-attachments/assets/9bc6b65a-64fc-4942-a685-76e391e55606" /></div>
-
-### 🧩 任务页：子代理拓扑 + 后台任务
-
-子代理树实时拓扑（运行状态、批量实时预览）+ 后台任务清单（退出码 / 实时输出 / 强制终止）；新子代理 / 新任务可自动展开侧边栏（可关）。
-
-<div align="center"><img width="880" alt="任务页：子代理拓扑" src="https://github.com/user-attachments/assets/dcd8ed2f-59fa-405b-937b-2d250f5034dd" /></div>
-
-### 💬 侧边对话(beta)
-
-Codex 风格侧边线程：**每个对话一个独立 Tab**；线程继承主会话完整上下文（含进行中回合，以 interrupted 诚实冻结）独立运行，不污染主会话；可持续追问、重启冷恢复；一键「保存为新会话」提升为顶层会话。
-
-<div align="center"><img width="880" alt="侧边对话(beta)" src="https://github.com/user-attachments/assets/3a338c36-f5de-4000-95f3-4b1cd04f60fc" /></div>
-
-### 🪟 双工作台：右侧栏 + 底部面板 + 分栏
-
-右侧栏与底部面板可同时展开；拖 Tab 到分栏边缘**拆分**、拖到中间**合并**（可跨面板）；面板宽高左缘/上缘拖拽调节；移动端自动合并为全宽抽屉。
-
-<div align="center"><img width="880" alt="双工作台（右侧栏 + 底部面板）" src="https://github.com/user-attachments/assets/dfdb875e-a1a8-4d4b-8340-353736b1708f" /></div>
-
-### ⚙️ 声明式设置
-
-设置页「侧边卡片」分区：每个 tab / 预览器一张小卡片，独立开关（高亮启用态 + 品牌开关滑块）；二级设置经卡片底部「功能设置」条弹窗（开关 / 文本 / 数字 / 下拉）；插件自有设置持久化在 `pluginSettings`。
-
-<div align="center"><img width="880" alt="声明式设置：侧边卡片" src="https://github.com/user-attachments/assets/0800ca64-621e-48da-b7df-aecfddc3ec29" /></div>
-
-### 📱 移动端
-
-窄屏（<768px）自动切换为全宽抽屉：底栏 tab 一次性并入右侧栏，触屏拖拽可调。
-
-<div align="center"><img width="360" alt="移动端全宽抽屉" src="https://github.com/user-attachments/assets/a82ba78a-f4cf-4d85-80e8-050a05beb144" /></div>
+| | |
+|---|---|
+| **🗂️ 文件工作台：资源管理器**<br/><sub>支持两种格式的资源管理器：内嵌在文件预览中 / 独立显示文件树。懒加载目录树、软链接按目标类型展示（目录软链接可展开、失效链接标红）、全局文件名搜索、上传文件/文件夹与拖放上传、右键菜单（在新 Tab 打开 / 在侧边打开 / 复制路径）、悬浮 `@文件` 一键引用进输入框。</sub><br/><div align="center"><img width="420" alt="文件资源管理器" src="https://github.com/user-attachments/assets/a410bfd2-a8ba-43e6-873e-22417756e94d" /></div> | **📝 Markdown · 图片 · PDF 内联预览**<br/><sub>Markdown 预览支持 **Mermaid 图表**（`securityLevel: 'strict'` 安全渲染 + 二次清洗；点击图表弹窗放大、滚轮缩放、拖拽平移）；图片 / PDF 走媒体路由内联展示；Office 三件套由生态插件补齐。</sub><br/><div align="center"><img width="420" alt="Markdown + Mermaid 预览" src="https://github.com/user-attachments/assets/fe0e5182-55bb-45cc-b98b-a2877c2bdd38" /></div> |
+| **🖥️ CodeMirror 代码编辑器**<br/><div align="center"><img width="420" alt="CodeMirror 代码编辑器" src="https://github.com/user-attachments/assets/b44b488e-568c-4ee0-b96c-e9c906598a77" /></div> | **🖼️ 图片内联预览**<br/><div align="center"><img width="420" alt="图片内联预览" src="https://github.com/user-attachments/assets/f9a58c30-5b7a-48b5-9e22-37d7e071f593" /></div> |
+| **💻 真实终端**<br/><sub>xterm.js + node-pty 真实 shell（不是模拟器）：断线重连 transcript 回放、shell / shellArgs 可配置（设置页或 `cordis.patch.yml`）、可选为模型注入 `terminal_*` 工具（agent 可直接开终端跑命令）。</sub><br/><div align="center"><img width="420" alt="真实终端" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div> | **🌿 Git 面板**<br/><sub>暂存 / 取消暂存 / 提交（`Ctrl+Enter`）/ 还原，历史列表；点击改动文件打开 **VSCode 式 diff tab**（红绿行级对比）。</sub><br/><div align="center"><img width="420" alt="Git 面板" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div> |
+| **🌐 内嵌浏览器**<br/><sub>多开网页 tab：后退 / 前进 / 刷新 / 地址栏；内容运行在**不透明源沙箱 iframe**（界面实时显示沙箱状态，可按页面临时解锁）；聊天里的外链点击可被接管到侧边栏打开（按协议分流，可配）。</sub><br/><div align="center"><img width="420" alt="内嵌浏览器" src="https://github.com/user-attachments/assets/9bc6b65a-64fc-4942-a685-76e391e55606" /></div> | **🧩 任务页：子代理拓扑 + 后台任务**<br/><sub>子代理树实时拓扑（运行状态、批量实时预览）+ 后台任务清单（退出码 / 实时输出 / 强制终止）；新子代理 / 新任务可自动展开侧边栏（可关）。</sub><br/><div align="center"><img width="420" alt="任务页：子代理拓扑" src="https://github.com/user-attachments/assets/dcd8ed2f-59fa-405b-937b-2d250f5034dd" /></div> |
+| **💬 侧边对话(beta)**<br/><sub>Codex 风格侧边线程：**每个对话一个独立 Tab**；线程继承主会话完整上下文（含进行中回合，以 interrupted 诚实冻结）独立运行，不污染主会话；可持续追问、重启冷恢复；一键「保存为新会话」提升为顶层会话。</sub><br/><div align="center"><img width="420" alt="侧边对话(beta)" src="https://github.com/user-attachments/assets/3a338c36-f5de-4000-95f3-4b1cd04f60fc" /></div> | **🪟 双工作台：右侧栏 + 底部面板 + 分栏**<br/><sub>右侧栏与底部面板可同时展开；拖 Tab 到分栏边缘**拆分**、拖到中间**合并**（可跨面板）；面板宽高左缘/上缘拖拽调节；移动端自动合并为全宽抽屉。</sub><br/><div align="center"><img width="420" alt="双工作台（右侧栏 + 底部面板）" src="https://github.com/user-attachments/assets/dfdb875e-a1a8-4d4b-8340-353736b1708f" /></div> |
+| **⚙️ 声明式设置**<br/><sub>设置页「侧边卡片」分区：每个 tab / 预览器一张小卡片，独立开关（高亮启用态 + 品牌开关滑块）；二级设置经卡片底部「功能设置」条弹窗（开关 / 文本 / 数字 / 下拉）；插件自有设置持久化在 `pluginSettings`。</sub><br/><div align="center"><img width="420" alt="声明式设置：侧边卡片" src="https://github.com/user-attachments/assets/0800ca64-621e-48da-b7df-aecfddc3ec29" /></div> | **📱 移动端**<br/><sub>窄屏（<768px）自动切换为全宽抽屉：底栏 tab 一次性并入右侧栏，触屏拖拽可调。</sub><br/><div align="center"><img width="360" alt="移动端全宽抽屉" src="https://github.com/user-attachments/assets/a82ba78a-f4cf-4d85-80e8-050a05beb144" /></div> |

 ## 🌐 插件生态

@@ -303,13 +250,28 @@ GitHub topic [`dsh-better-sidebar`](https://github.com/topics/dsh-better-sidebar

 ## 🆕 最近更新

-<div align="center">
-  <a href="https://github.com/user-attachments/assets/d2aea86b-a776-4f01-a6b8-b26b27314336"><img width="33%" alt="侧边栏" src="https://github.com/user-attachments/assets/d2aea86b-a776-4f01-a6b8-b26b27314336" /></a>
-  <a href="https://github.com/user-attachments/assets/946f7028-4967-461e-a750-d1b5056b62d0"><img width="33%" alt="服务化基座截图" src="https://github.com/user-attachments/assets/946f7028-4967-461e-a750-d1b5056b62d0" /></a>
-</div>
-
 **支持的 DSH 版本**：<a href="https://www.npmjs.com/package/@deepseek-ai/dsh?activeTab=versions"><img alt="支持的 DSH 版本：0.1.0-rc.8 · 0.1.1-rc.1 · 0.1.1-rc.2" src="https://img.shields.io/badge/DSH-0.1.0--rc.8_%C2%B7_0.1.1--rc.1_%C2%B7_0.1.1--rc.2-4d6bfe" /></a> · 完整发布历史见 [Releases](https://github.com/omdsh-dev/DSH-better-sidebar/releases)

+### v0.15.2
+
+自 v0.15.1 以来的全部更改：
+
+**✨ 新功能**
+
+- 🗂️ **文件树「在应用中打开」子菜单**（[#334](https://github.com/omdsh-dev/DSH-better-sidebar/pull/334)）：文件树右键菜单新增「在应用中打开 >」子菜单——内置打开方式（资源管理器显示/选中、VS Code、Cursor、Zed），每行右侧图钉可固定为右键菜单顶层直达项（再点取消）；配置可选 SSH host 后 VSCode 系条目改用 `vscode-remote/ssh-remote+<host>/<path>` 协议打开，本地专用条目自动隐藏；支持自定义编辑器（名称 + URL 模板 `{path}` + 是否 VSCode 系，配置入口在 Files 卡片齿轮弹窗）。打开动作经新宿主路由 `POST /sidebar/api/open.external`（argv 数组 spawn，无 shell 注入）（[设计文档](docs/plans/2026-08-22-open-with-menu-design.md)）
+- 📑 **Tab 右键菜单**（[#331](https://github.com/omdsh-dev/DSH-better-sidebar/pull/331)）：页签右键提供「关闭 / 关闭其他页签 / 关闭左侧页签 / 关闭右侧页签」，作用范围为当前 pane（标签组），无可关对象时置灰；仅打开菜单、不切换激活页签；批量关闭逐条走既有 `onClose` 路径，生命周期完整
+- 📄 **Diff 文件默认折叠**（[#270](https://github.com/omdsh-dev/DSH-better-sidebar/pull/270)）：改动文件头部改为可访问的展开/折叠控件；识别出的源文件默认展开，测试 / 文档 / 生成文件 / lockfile 与未知类型默认折叠；保留现有 500 行上限
+- 📖 **README 更新**：特性巡礼改为表格展示（每行两张图，节省空间）；社区补全微信群 / QQ 群二维码（[#325](https://github.com/omdsh-dev/DSH-better-sidebar/pull/325)，QQ 群 577011007）
+
+**🐛 修复**
+
+- 🪟 **空分栏清理**（[#268](https://github.com/omdsh-dev/DSH-better-sidebar/pull/268)）：持久化的 split pane 在临时 diff tab 被清理后遗留全尺寸空分栏——`sanitizeState` 现在同时修剪空的 split leaf，并修复修剪后的失效激活 pane 指针；整个工作台为空时保留唯一空 pane
+- 🖥️ **Windows 下隐藏 Git 子进程窗口**（[#301](https://github.com/omdsh-dev/DSH-better-sidebar/pull/301)，关闭 [#124](https://github.com/omdsh-dev/DSH-better-sidebar/issues/124)）：`runGit()` 统一加 `windowsHide: true`，仓库状态轮询与操作不再闪现控制台窗口（其他平台行为不变）
+- 📁 **未跟踪文件夹内文件差异**（[#242](https://github.com/omdsh-dev/DSH-better-sidebar/pull/242)）：`git status` 从 `--untracked-files=normal` 切换为 `--untracked-files=all`——新文件夹内每个文件独立成行、可正常加载差异（修正 `fs.read` 报 "is a directory"，与 VSCode 默认行为一致）
+- ⚡ **开关/拖拽每帧 React 重渲染消除**（关闭 [#315](https://github.com/omdsh-dev/DSH-better-sidebar/issues/315)）：centerRect 改 ref + 底栏 DOM 直写（零 React 渲染）；TabContent memo（显式比较器）；新增 frame-batcher 对 Divider/dock 拖拽按帧合并；拖拽期跳过无意义 locate。4x CPU 节流 A/B：开关 >17ms 帧 collapse 19→6 / expand 24→4~6，p95 21ms→15ms；拖拽不变（非回归）
+
+<details>
+<summary><b>历史版本（v0.12.0 – v0.15.1）</b></summary>
 ### v0.15.1

 自 v0.15.0 以来的全部更改：
@@ -345,9 +307,6 @@ GitHub topic [`dsh-better-sidebar`](https://github.com/topics/dsh-better-sidebar
 - 🔧 **适配 DSH 0.1.1-rc.1 / rc.2（@next）**（[#297](https://github.com/omdsh-dev/DSH-better-sidebar/pull/297) [#305](https://github.com/omdsh-dev/DSH-better-sidebar/pull/305)）：无代码逻辑改动
 - 🔒 **上传链路安全加固**（[#239](https://github.com/omdsh-dev/DSH-better-sidebar/pull/239)）：`relativePath` 空段 / 绝对路径显式拒绝；临时文件唯一命名（并发上传互不干扰、崩溃不阻塞）；写流错误监听（磁盘失败不崩溃进程）；客户端错误码与服务端统一、413 本地化

-<details>
-<summary><b>历史版本（v0.12.0 – v0.14.0）</b></summary>
-
 ### v0.14.0

 > ⚠️ 本版起需要 DSH ≥ 0.1.0-rc.8。自 v0.13.1 以来的全部更改：
@@ -406,6 +365,15 @@ GitHub topic [`dsh-better-sidebar`](https://github.com/topics/dsh-better-sidebar

 </details>

+## 💬 社区
+
+推荐添加QQ群(577011007)
+
+<div align="center">
+  <img width="220" alt="微信群二维码" src="https://github.com/user-attachments/assets/39caafc7-9629-4b13-bb2b-eac17eab5b6a" />
+  <img width="220" alt="QQ群二维码" src="https://github.com/user-attachments/assets/9be34629-26ef-4537-aad4-1393c147f81c" />
+</div>
+
 ## ⌨️ 快捷键

 | 操作 | 按键 |
@@ -413,6 +381,7 @@ GitHub topic [`dsh-better-sidebar`](https://github.com/topics/dsh-better-sidebar
 | 保存编辑 | `Ctrl/Cmd + S` |
 | Git 提交 | `Ctrl + Enter` |
 | 关闭 Tab | 鼠标中键 |
+| Tab 右键菜单 | 关闭 / 关闭其他页签 / 关闭左侧页签 / 关闭右侧页签（当前标签组） |
 | 拆分/合并分栏 | 拖 Tab 到分栏边缘 / 中间 |
 | 引用文件到输入框 | 悬浮行尾 `@文件` 按钮 |
 | 复制文件路径 | 右键行 → 复制相对/绝对地址 |
@@ -462,19 +431,6 @@ pnpm watch        # tsdown --watch

 Windows / Linux / macOS 三平台适配（macOS 日常验证；其余经单元测试覆盖）；`node-pty` 优先预编译二进制，失败需编译工具链（Windows VS Build Tools / Linux make+g+++python3 / macOS Xcode CLT）。

-## 💬 社区
-
-微信 / QQ 交流群二维码将在此处展示。上传二维码图片（拖入任意 issue / comment 即可获得 `user-attachments` 链接）后，替换下方 `src` 并取消注释：
-
-<div align="center">
-  <!-- 微信群二维码
-  <img width="220" alt="微信群二维码" src="https://github.com/user-attachments/assets/REPLACE_ME" />
-  -->
-  <!-- QQ 群二维码
-  <img width="220" alt="QQ群二维码" src="https://github.com/user-attachments/assets/REPLACE_ME" />
-  -->
-</div>
-
 ## 🤝 参与贡献

 - **代码改动走 PR**：`feat/*` / `fix/*` 分支开发 → `gh pr create`；纯文档改动可直接推 main
@@ -151,69 +151,16 @@ Update: `git pull && pnpm install && pnpm build` → `node scripts/package-regis

 ## 🖼️ Feature Tour

-> Below are real UI screenshots.
+> Below are real UI screenshots (two per row; click to zoom).

-### 🗂️ File Workbench: Explorer
-
-Two explorer modes: embedded in the file preview / standalone file tree. Lazy-loading directory tree, symlinks classified by target kind (directory links expand, dangling links flagged), global filename search, file/folder upload buttons plus drag-drop upload, context menu (open in new tab / open to the side / copy paths), and a hover `@file` button that references a file straight into the composer.
-
-<div align="center"><img width="880" alt="File explorer" src="https://github.com/user-attachments/assets/a410bfd2-a8ba-43e6-873e-22417756e94d" /></div>
-<div align="center"><img width="880" alt="CodeMirror editor" src="https://github.com/user-attachments/assets/b44b488e-568c-4ee0-b96c-e9c906598a77" /></div>
-
-### 📝 Inline Preview: Markdown · Images · PDF
-
-The Markdown preview renders **Mermaid diagrams** (strict-mode safe rendering + a second sanitize pass; click a diagram for a zoom modal with wheel-zoom and drag-pan); images / PDFs display inline via the media route; the Office suite is covered by an ecosystem plugin.
-
-<div align="center"><img width="880" alt="Markdown + Mermaid preview" src="https://github.com/user-attachments/assets/fe0e5182-55bb-45cc-b98b-a2877c2bdd38" /></div>
-<div align="center"><img width="880" alt="Inline image preview" src="https://github.com/user-attachments/assets/f9a58c30-5b7a-48b5-9e22-37d7e071f593" /></div>
-
-### 💻 Real Terminal
-
-xterm.js + node-pty real shell (not an emulator): transcript replay on reconnect, configurable shell / shellArgs (settings page or `cordis.patch.yml`), and optional `terminal_*` model tools so the agent can open terminals and run commands itself.
-
-<div align="center"><img width="880" alt="Real terminal" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div>
-
-### 🌿 Git Panel
-
-Stage / unstage / commit (`Ctrl+Enter`) / revert, plus a history list; clicking a changed file opens a **VSCode-style diff tab** (line-level red/green).
-
-<div align="center"><img width="880" alt="Git panel" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div>
-
-### 🌐 Embedded Browser
-
-Multiple web tabs with back / forward / reload / address bar; content runs in an **opaque-origin sandboxed iframe** (live sandbox status in the UI, per-page temporary unlock available); external-link clicks in the chat can be taken over into the sidebar (protocol-based routing, configurable).
-
-<div align="center"><img width="880" alt="Embedded browser" src="https://github.com/user-attachments/assets/9bc6b65a-64fc-4942-a685-76e391e55606" /></div>
-
-### 🧩 Tasks: Agent Topology + Background Jobs
-
-Live subagent-tree topology (run states, batched live previews) plus the background-jobs list (exit codes / live output / force-kill); new subagents / jobs can auto-expand the sidebar (configurable).
-
-<div align="center"><img width="880" alt="Tasks: subagent topology" src="https://github.com/user-attachments/assets/dcd8ed2f-59fa-405b-937b-2d250f5034dd" /></div>
-
-### 💬 Side Chat (beta)
-
-Codex-style side threads: **one independent tab per conversation**; the thread inherits the parent's full context (including the in-progress turn, honestly frozen as "interrupted") and runs independently without polluting the main session; follow-ups survive restarts; one click promotes the thread to a top-level session.
-
-<div align="center"><img width="880" alt="Side Chat (beta)" src="https://github.com/user-attachments/assets/3a338c36-f5de-4000-95f3-4b1cd04f60fc" /></div>
-
-### 🪟 Dual Workbench: Sidebar + Bottom Panel + Split Panes
-
-The right sidebar and the bottom panel can stay open together; drag a tab to a pane edge to **split**, to the middle to **merge** (works across panels); panel width/height drag from the left/top edge; on mobile everything merges into a full-width drawer.
-
-<div align="center"><img width="880" alt="Dual workbench (right sidebar + bottom panel)" src="https://github.com/user-attachments/assets/dfdb875e-a1a8-4d4b-8340-353736b1708f" /></div>
-
-### ⚙️ Declarative Settings
-
-The "Side card" section in DSH settings: one small card per tab / viewer with an independent toggle (highlighted enabled state + brand switch); secondary settings open from the "Feature settings" strip at the card bottom (switch / text / number / select rows); plugin-owned settings persist under `pluginSettings`.
-
-<div align="center"><img width="880" alt="Declarative settings: side cards" src="https://github.com/user-attachments/assets/0800ca64-621e-48da-b7df-aecfddc3ec29" /></div>
-
-### 📱 Mobile
-
-On narrow screens (<768px) the panels become a full-width drawer: bottom-panel tabs merge into the sidebar once, with touch-friendly dragging.
-
-<div align="center"><img width="360" alt="Mobile full-width drawer" src="https://github.com/user-attachments/assets/a82ba78a-f4cf-4d85-80e8-050a05beb144" /></div>
+| | |
+|---|---|
+| **🗂️ File Workbench: Explorer**<br/><sub>Two explorer modes: embedded in the file preview / standalone file tree. Lazy-loading directory tree, symlinks classified by target kind (directory links expand, dangling links flagged), global filename search, file/folder upload buttons plus drag-drop upload, context menu (open in new tab / open to the side / copy paths), and a hover `@file` button that references a file straight into the composer.</sub><br/><div align="center"><img width="420" alt="File explorer" src="https://github.com/user-attachments/assets/a410bfd2-a8ba-43e6-873e-22417756e94d" /></div> | **📝 Inline Preview: Markdown · Images · PDF**<br/><sub>The Markdown preview renders **Mermaid diagrams** (strict-mode safe rendering + a second sanitize pass; click a diagram for a zoom modal with wheel-zoom and drag-pan); images / PDFs display inline via the media route; the Office suite is covered by an ecosystem plugin.</sub><br/><div align="center"><img width="420" alt="Markdown + Mermaid preview" src="https://github.com/user-attachments/assets/fe0e5182-55bb-45cc-b98b-a2877c2bdd38" /></div> |
+| **🖥️ CodeMirror editor**<br/><div align="center"><img width="420" alt="CodeMirror editor" src="https://github.com/user-attachments/assets/b44b488e-568c-4ee0-b96c-e9c906598a77" /></div> | **🖼️ Inline image preview**<br/><div align="center"><img width="420" alt="Inline image preview" src="https://github.com/user-attachments/assets/f9a58c30-5b7a-48b5-9e22-37d7e071f593" /></div> |
+| **💻 Real Terminal**<br/><sub>xterm.js + node-pty real shell (not an emulator): transcript replay on reconnect, configurable shell / shellArgs (settings page or `cordis.patch.yml`), and optional `terminal_*` model tools so the agent can open terminals and run commands itself.</sub><br/><div align="center"><img width="420" alt="Real terminal" src="https://github.com/user-attachments/assets/0dad6ad3-ff3f-4b5a-86d2-f832ce65323e" /></div> | **🌿 Git Panel**<br/><sub>Stage / unstage / commit (`Ctrl+Enter`) / revert, plus a history list; clicking a changed file opens a **VSCode-style diff tab** (line-level red/green).</sub><br/><div align="center"><img width="420" alt="Git panel" src="https://github.com/user-attachments/assets/e7fc1220-305f-4bca-8583-e77ab4f4fa78" /></div> |
+| **🌐 Embedded Browser**<br/><sub>Multiple web tabs with back / forward / reload / address bar; content runs in an **opaque-origin sandboxed iframe** (live sandbox status in the UI, per-page temporary unlock available); external-link clicks in the chat can be taken over into the sidebar (protocol-based routing, configurable).</sub><br/><div align="center"><img width="420" alt="Embedded browser" src="https://github.com/user-attachments/assets/9bc6b65a-64fc-4942-a685-76e391e55606" /></div> | **🧩 Tasks: Agent Topology + Background Jobs**<br/><sub>Live subagent-tree topology (run states, batched live previews) plus the background-jobs list (exit codes / live output / force-kill); new subagents / jobs can auto-expand the sidebar (configurable).</sub><br/><div align="center"><img width="420" alt="Tasks: subagent topology" src="https://github.com/user-attachments/assets/dcd8ed2f-59fa-405b-937b-2d250f5034dd" /></div> |
+| **💬 Side Chat (beta)**<br/><sub>Codex-style side threads: **one independent tab per conversation**; the thread inherits the parent's full context (including the in-progress turn, honestly frozen as "interrupted") and runs independently without polluting the main session; follow-ups survive restarts; one click promotes the thread to a top-level session.</sub><br/><div align="center"><img width="420" alt="Side Chat (beta)" src="https://github.com/user-attachments/assets/3a338c36-f5de-4000-95f3-4b1cd04f60fc" /></div> | **🪟 Dual Workbench: Sidebar + Bottom Panel + Split Panes**<br/><sub>The right sidebar and the bottom panel can stay open together; drag a tab to a pane edge to **split**, to the middle to **merge** (works across panels); panel width/height drag from the left/top edge; on mobile everything merges into a full-width drawer.</sub><br/><div align="center"><img width="420" alt="Dual workbench (right sidebar + bottom panel)" src="https://github.com/user-attachments/assets/dfdb875e-a1a8-4d4b-8340-353736b1708f" /></div> |
+| **⚙️ Declarative Settings**<br/><sub>The "Side card" section in DSH settings: one small card per tab / viewer with an independent toggle (highlighted enabled state + brand switch); secondary settings open from the "Feature settings" strip at the card bottom (switch / text / number / select rows); plugin-owned settings persist under `pluginSettings`.</sub><br/><div align="center"><img width="420" alt="Declarative settings: side cards" src="https://github.com/user-attachments/assets/0800ca64-621e-48da-b7df-aecfddc3ec29" /></div> | **📱 Mobile**<br/><sub>On narrow screens (<768px) the panels become a full-width drawer: bottom-panel tabs merge into the sidebar once, with touch-friendly dragging.</sub><br/><div align="center"><img width="360" alt="Mobile full-width drawer" src="https://github.com/user-attachments/assets/a82ba78a-f4cf-4d85-80e8-050a05beb144" /></div> |

 ## 🌐 Plugin Ecosystem

@@ -310,6 +257,27 @@ The GitHub topic [`dsh-better-sidebar`](https://github.com/topics/dsh-better-sid

 **Supported DSH versions**: <a href="https://www.npmjs.com/package/@deepseek-ai/dsh?activeTab=versions"><img alt="Supported DSH versions: 0.1.0-rc.8 · 0.1.1-rc.1 · 0.1.1-rc.2" src="https://img.shields.io/badge/DSH-0.1.0--rc.8_%C2%B7_0.1.1--rc.1_%C2%B7_0.1.1--rc.2-4d6bfe" /></a> · full release history on the [Releases](https://github.com/omdsh-dev/DSH-better-sidebar/releases) page

+### v0.15.2
+
+All changes since v0.15.1:
+
+**✨ New features**
+
+- 🗂️ **"Open in app" submenu in the file tree** ([#334](https://github.com/omdsh-dev/DSH-better-sidebar/pull/334)): the file-tree context menu gains an "Open in app >" submenu — built-in openers (reveal/select in file manager, VS Code, Cursor, Zed), each with a pin button that promotes it to a top-level context-menu item (click again to unpin); with an optional SSH host configured, VSCode-family entries switch to the `vscode-remote/ssh-remote+<host>/<path>` protocol and local-only entries hide automatically; custom editors supported (name + URL template with `{path}` + "VSCode-family" flag, configured in the Files card gear popup). Open actions go through the new host route `POST /sidebar/api/open.external` (argv-array spawn, no shell injection) ([design](docs/plans/2026-08-22-open-with-menu-design.md))
+- 📑 **Tab context menu** ([#331](https://github.com/omdsh-dev/DSH-better-sidebar/pull/331)): right-clicking a tab offers **Close / Close others / Close to the left / Close to the right**, scoped to the current pane (tab group); items grey out when there is nothing to close; the menu only opens — it never switches the active tab; bulk closes go through the existing per-tab `onClose` path so lifecycle callbacks, pty release and agent-terminal shutdown all stay intact
+- 📄 **Diff files collapsed by default** ([#270](https://github.com/omdsh-dev/DSH-better-sidebar/pull/270)): each changed-file header is now an accessible expand/collapse control; recognized source files expand by default while tests, docs, generated files, lockfiles and unknown types stay collapsed; the existing 500-row cap for expanded content is preserved
+- 📖 **README update**: feature tour converted to a table (two screenshots per row, saves space); community section now shows the WeChat group and QQ group QR codes ([#325](https://github.com/omdsh-dev/DSH-better-sidebar/pull/325), QQ group 577011007)
+
+**🐛 Fixes**
+
+- 🪟 **Prune empty restored panes** ([#268](https://github.com/omdsh-dev/DSH-better-sidebar/pull/268)): persisted split panes left empty when ephemeral diff tabs were dropped no longer survive as full-size blanks — `sanitizeState` now also prunes the empty split leaf and repairs the stale active-pane pointer; a fully empty workbench keeps its single empty pane
+- 🖥️ **Hide spawned git windows on Windows** ([#301](https://github.com/omdsh-dev/DSH-better-sidebar/pull/301), fixes [#124](https://github.com/omdsh-dev/DSH-better-sidebar/issues/124)): the shared `runGit()` spawn options now set `windowsHide: true`, so repo-status polling and git actions no longer flash console windows on Windows (no behavior change on other platforms)
+- 📁 **Untracked files inside new folders** ([#242](https://github.com/omdsh-dev/DSH-better-sidebar/pull/242)): `git status` switched from `--untracked-files=normal` to `--untracked-files=all` — each file inside a new folder now shows as its own row and its diff can be loaded (no more `fs.read` "is a directory" error), matching VSCode's default behavior
+- ⚡ **Per-frame React re-renders eliminated for toggles/drags** (closes [#315](https://github.com/omdsh-dev/DSH-better-sidebar/issues/315)): `centerRect` moved to a ref with direct DOM writes to the bottom bar (zero React renders); `TabContent` memoized with an explicit comparator; a new frame-batcher coalesces Divider/dock drags per frame; meaningless locate passes skipped during drags. 4x CPU-throttled A/B: >17ms frames on toggle collapse 19→6 / expand 24→4~6, p95 21ms→15ms; drags unchanged (non-regression)
+
+<details>
+<summary><b>Older releases (v0.12.0 – v0.15.1)</b></summary>
+
 ### v0.15.1

 All changes since v0.15.0:
@@ -345,9 +313,6 @@ All changes since v0.14.0:
 - 🔧 **Adapted to DSH 0.1.1-rc.1 / rc.2 (@next)** ([#297](https://github.com/omdsh-dev/DSH-better-sidebar/pull/297) [#305](https://github.com/omdsh-dev/DSH-better-sidebar/pull/305)): no code changes needed
 - 🔒 **Upload-chain hardening** ([#239](https://github.com/omdsh-dev/DSH-better-sidebar/pull/239)): empty and absolute `relativePath` segments are refused outright; uniquely named temp files (concurrent uploads stay independent, crashed processes never block later uploads); write-stream error listeners (a failing disk can no longer crash the host); client error codes unified with the wire (`too-large`), 413s localized

-<details>
-<summary><b>Older releases (v0.12.0 – v0.14.0)</b></summary>
-
 ### v0.14.0

 > ⚠️ This release requires DSH ≥ 0.1.0-rc.8. All changes since v0.13.1:
@@ -413,6 +378,7 @@ All changes since v0.14.0:
 | Save edits | `Ctrl/Cmd + S` |
 | Git commit | `Ctrl + Enter` |
 | Close tab | Middle mouse button |
+| Tab context menu (right-click) | Close / Close Other Tabs / Close Tabs to the Left / Close Tabs to the Right (current pane) |
 | Split / merge panes | Drag tab to pane edge / middle |
 | Reference file to input | Hover the `@file` button at end of line |
 | Copy file path | Right-click row → copy relative/absolute path |
@@ -0,0 +1,106 @@
+# 文件树「打开方式」子菜单设计（2026-08-22）
+
+> 状态：已实现（分支 `feat/open-with-menu`）。本文档记录功能设计、关键取舍与实施偏差。
+
+## 目标
+
+文件树（`FileTree`）右键菜单新增「在应用中打开 >」子菜单：
+
+- 内置 **资源管理器（在文件管理器中显示）、VS Code、Cursor、Zed** 四个打开方式；每个子菜单行右侧有**图钉**，点击可把该方式固定为右键菜单的**顶层直达项**（再点取消固定）。
+- **远端 SSH**：设置中配置可选 SSH host（`user@host` 或 `~/.ssh/config` 别名）。非空即整个工作区视为远端：VSCode 系条目（VS Code / Cursor / 自定义且勾选"VSCode 系"）改用 `<scheme>://vscode-remote/ssh-remote+<host>/<path>` 打开；本地专用条目（资源管理器 / Zed / 非 VSCode 系自定义）从菜单隐藏。
+- **自定义编辑器**：名称 + URL 模板（`{path}` 占位符，如 `cursor://file/{path}`）+ 「是否 VSCode 系」开关；配置入口在**侧边栏设置 Files 卡片齿轮**（与既有 `editorExplorer` 下拉同一弹窗）。
+- 打开动作经宿主新路由 `POST /sidebar/api/open.external` 执行（argv 数组 spawn，无 shell 注入），浏览器模式与 DSH Desktop 行为一致；**不经过** `ctx.workspaces.openPath`（该入口已被 `wrapOpenPath` 劫持到侧边栏编辑器，见 `src/client/openpath-intercept.ts`）。
+
+## 调研结论（reuse gate）
+
+- DSH checkout（`~/.dsh/source/current`）无"文件树 open-with"、无 SSH 远程会话、无 `vscode://` 开启器；`host.openPath` 只能"默认应用打开"，无法指定编辑器、无 reveal/select 语义 → 需要新增。
+- dsh-external hub 无同类成品；`dsh-open-in-vscode` 是工作区行菜单、依赖外部 slot，不适用。
+- primitives `Menu` 原生支持 `submenu?: readonly MenuItem[]`（子项点击走 `onSelect(child.id)`），`label: ReactNode` 可内嵌图钉；无现成图钉/品牌图标 → 引入 `react-icons`（`vsc` codicons 图钉 `VscPin`/`VscPinned` 与文件树 `VscFile`/`VscFolder(Opened)`、`si` 品牌剪影 Cursor/Zed、菜单父行 `VscLinkExternal`），VS Code 品牌剪影因 simple-icons 后期版本受微软商标政策下架而内嵌自 simple-icons@11.0.0（CC0，`IconVscode16`）；菜单行图标统一 16px 与 DSH 原生菜单一致，子菜单父行的 `>` chevron 由 label 内右对齐元素提供（基元不渲染）。⚠️ react-icons 的 exports 把 `require` 排在 `import` 前，tsdown 共享 conditionNames 会选中不可树摇的 CJS 入口（bundle +6.4MB）——`tsdown.config.ts` 用 `resolve.alias` 钉死 `si`/`vsc` 的 ESM 入口，树摇后仅 +12KB。
+
+## 数据模型
+
+持久化在 `pluginSettings['editor'].openWith`（宿主 schema 的开放 map，无需改 PrefsSchema）：
+
+```json
+{
+  "openWith": {
+    "sshHost": "",
+    "customEditors": [
+      { "id": "custom:<uuid>", "name": "Windsurf", "urlTemplate": "windsurf://file/{path}", "isVscodeFamily": false }
+    ],
+    "pinned": ["vscode", "custom:<uuid>"]
+  }
+}
+```
+
+- `parseOpenWithConfig`（`src/client/open-with.ts`）容错解析：坏行丢弃、未知 pinned 在解析目标时剪枝；**结构合法但未填完的行（空 name/模板）保留**——设置面板正在编辑的行必须能在弹窗往返中存活，由菜单侧的 `isValidCustomEditor` 过滤。
+- 目标 id：内置 `explorer` / `vscode` / `cursor` / `zed`；自定义 `custom:<uuid>`。
+- URL 构建：
+  - 本地：模板原文替换 `{path}`（`vscode://file//home/u/f.ts`——POSIX 绝对路径自带前导 `/`，与 VS Code 官方文档 `vscode://file/c:/…` 的约定一致；反斜杠归一化为 `/`）。
+  - SSH（VSCode 系）：`<scheme>://vscode-remote/ssh-remote+<host>/<path>`，路径保留前导 `/`（如 `…+dev/home/u/f.ts`，与社区约定一致）。
+  - 模板无 `scheme://` 或无 `{path}` → 返回 undefined（不打开）。
+
+## 菜单结构（文件行与目录行一致）
+
+```
+在新 Tab 中打开                    ← 既有
+在侧边打开                        ← 既有
+----------------------------
+VS Code            (SSH)         ← pinned 直达项（按内置顺序 + 自定义追加）
+Cursor             (SSH)
+----------------------------
+在应用中打开 >                    ← 子菜单父项（始终在 pinned 之后）
+   资源管理器      📌
+   VS Code         📌(激活)
+   Cursor          📌(激活)
+   Zed             📌
+   Windsurf        📌
+下载                             ← 既有（仅文件行）
+复制相对地址 / 复制绝对地址         ← 既有
+```
+
+- 图钉是 `label` 内的 `<span role="button" tabIndex={-1}>`（Menu 行本身是 `<button>`，嵌套原生 button 不合法）；`stopPropagation` + `preventDefault` 使其**不关闭菜单、不触发行选择**，点击后经响应式 blob 重渲染立即翻转。
+- 未接线（props 缺省）或 SSH 过滤后无目标 → 整个区块隐藏，旧行为/旧测试不变。
+
+## 设置面板：`settings.render` seam 扩展
+
+**实施偏差（与最初"render 独占"契约不同，需同步文档）**：`SettingsBody`（`src/client/SideCardSection.tsx`）原先"有 `render` 就整个替换行列表"。本功能需要**行列表（`editorExplorer` 下拉）与自定义面板共存**，因此把 seam 改为：
+
+> `render` 给定时**追加**渲染在行列表（`toggles` / `pluginToggles`）之后；未声明行列表时与旧行为一致（单独渲染）。
+
+- 仓库内无既有 render 使用者，`tests/side-card-section.spec.tsx` 无"render 独占"断言，风险可控；`AGENTS.md` §3.1/§5 与本文档同步更新。
+- 面板组件 `OpenWithSettings`：SSH host 输入 + 自定义编辑器行（名称/模板/VSCode 系/删除）+「添加」；每次变更整体提交 `updatePluginSetting('openWith', next)`（含 pinned 原样保留）。
+- 图钉写入走 `src/client/plugin-settings.ts` 的 `updatePluginSettings`：Promise 链串行化 + `api.settingsUpdate` 后 `store.setPrefs(parsePrefs(view.value))`，避免快速连点丢写。（设置弹窗内部有自己独立的串行 commit，二者极少重叠。）
+
+## 宿主路由
+
+`POST /sidebar/api/open.external`（`src/index.ts` `buildApi`，与其他方法同 fence + 错误包裹）：
+
+```ts
+{ action: 'reveal', path }  // 在文件管理器中显示/选中
+{ action: 'url', url }      // 交给注册的协议处理器
+```
+
+- `src/open-external.ts`：纯函数 `revealCommand` / `urlCommand`（platform 可注入，单测覆盖三平台）+ `launchExternal`（`spawn(..., { detached: true, stdio: 'ignore' })` + `unref`）。
+- `reveal`：darwin `open -R`；win32 `explorer.exe /select,`；linux `xdg-open <父目录>`（无统一 select 协议，KISS 打开所在目录）。
+- `url`：darwin `open`；win32 `rundll32 url.dll,FileProtocolHandler`（备选 `cmd /c start ""`）；linux `xdg-open`。
+- 校验：`reveal` 路径必须绝对（`requireAbsolute`）；`url` 必须是 `scheme://` 自定义协议（拒绝 http/https）。
+- **Windows 平台命令为约定实现，需在 Windows 实机验证**（本机为 macOS；CI 覆盖 linux）。
+
+## 已知限制
+
+- 路径含 `#`/`?` 的文件名经 URL 打开可能被浏览器当作 fragment/query（不处理，注释说明）。
+- 编辑器未安装/协议未注册：由 OS 弹提示或静默失败，不做安装检测。
+- 自定义编辑器仅支持 URL 模板式，不支持 CLI 命令式；无 `{dir}` 占位符。
+- Linux reveal 退化为打开所在目录（精确 select 需要各文件管理器私有协议）。
+- SSH 模式为**全局**（非每会话）：DSH 无远程会话概念，文件树路径即宿主路径；该模型对应"DSH 跑在远端开发机上"的场景。
+
+## 测试
+
+- `tests/open-with.spec.ts`：解析容错、目标解析与 SSH 过滤、URL 构建（本地/SSH/custom/坏模板）、校验器。
+- `tests/open-external.spec.ts`：三平台命令表、URL 校验、spawn 前校验。
+- `tests/file-tree-open-with.spec.tsx`（jsdom）：右键 → 子菜单/图钉；pin 不选中不关闭；选子项回调关闭菜单；SSH 标签后缀；未接线隐藏。
+- `tests/open-with-settings.spec.tsx`：SSH 输入、添加/删除（删除剪枝 pinned）、无效提示、VSCode 系开关。
+- `tests/side-card-section.spec.tsx`：`SettingsBody` 行列表 + render 共存、仅 render 时不变。
+- `tests/builtins.spec.ts`：editor 描述符断言补 `settings.render`。
+- 全量 `pnpm test`（810 passed）、`pnpm typecheck`、`pnpm build` 全绿；未跑挂载冒烟（由 CI plugin-mount 门禁覆盖）。
@@ -1,6 +1,6 @@
 {
  "id": "dsh-external/dsh-better-sidebar",
-  "version": "0.15.1",
+  "version": "0.15.2",
  "main": "./lib/index.js",
  "description": "VSCode 风格右侧侧边栏：文件资源管理器 / 编辑器 / 终端 / Git / 浏览器，按会话隔离。暴露服务供其他插件注册侧边栏页面和文件预览器",
  "engines": {
@@ -1,6 +1,6 @@
 {
  "name": "dsh-better-sidebar",
-  "version": "0.15.1",
+  "version": "0.15.2",
  "description": "DSH web plugin: a VSCode-like right sidebar (explorer / editor / terminal / git / browser), isolated per conversation session. Exposes a service for other plugins to register sidebar tabs and file viewers.",
  "type": "module",
  "repository": {
@@ -96,8 +96,8 @@
    "@deepseek-ai/dsh-invariants": "^0.1.0-rc.8",
    "@deepseek-ai/dsh-llm": "^0.1.0-rc.8",
    "@deepseek-ai/dsh-session": "^0.1.0-rc.8",
-    "@deepseek-ai/dsh-subagent": "^0.1.0-rc.8",
    "@deepseek-ai/dsh-settings": "^0.1.0-rc.8",
+    "@deepseek-ai/dsh-subagent": "^0.1.0-rc.8",
    "@deepseek-ai/dsh-tools": "^0.1.0-rc.8",
    "cordis": "^4.0.0-rc.8",
    "react": "^18.2.0",
@@ -133,6 +133,7 @@
    "clsx": "^2.1.1",
    "mermaid": "^11.16.1",
    "node-pty": "^1.1.0",
+    "react-icons": "5.7.0",
    "rxjs": "^7.8.2",
    "schemastery": "^3.18.0",
    "ws": "^8.18.0"
@@ -83,6 +83,9 @@ importers:
      node-pty:
        specifier: ^1.1.0
        version: 1.1.0
+      react-icons:
+        specifier: 5.7.0
+        version: 5.7.0(react@18.2.0)
      rxjs:
        specifier: ^7.8.2
        version: 7.8.2
@@ -2302,6 +2305,11 @@ packages:
    peerDependencies:
      react: ^18.2.0

+  react-icons@5.7.0:
+    resolution: {integrity: sha512-LBLy340Rzqy6+/yVhZKT3B/QpP1BZaesGqasf09HPOBzRarcDIFH0WwXlXQfE7q7ipxK4MSiC5DIBWURCny6fw==}
+    peerDependencies:
+      react: '*'
+
  react@18.2.0:
    resolution: {integrity: sha512-/3IjMdb2L9QbBdWiW5e3P2/npwMBaU9mHCSCUzNln0ZCYbcfTsGbTJrU/kGemdH2IWmB2ioZ+zkxtmq6g09fGQ==}
    engines: {node: '>=0.10.0'}
@@ -5068,6 +5076,10 @@ snapshots:
      react: 18.2.0
      scheduler: 0.23.0

+  react-icons@5.7.0(react@18.2.0):
+    dependencies:
+      react: 18.2.0
+
  react@18.2.0:
    dependencies:
      loose-envify: 1.4.0
@@ -22,9 +22,9 @@ import {
  IconChevronRightOutline14,
  IconLinkOutline14,
  IconRefreshOutline14,
-  IconRightUpOutline16,
  IconWarningOutline16,
 } from '@deepseek-ai/dsh-client-ui-primitives'
+import { VscLinkExternal } from 'react-icons/vsc'
 import { api } from './api.ts'
 import { embeddabilityOf, normalizeBrowserUrl } from './browser.ts'
 import { patchTab } from './state.ts'
@@ -186,7 +186,7 @@ export function BrowserView(props: TabComponentProps) {
            if (url !== undefined) window.open(url, '_blank', 'noopener')
          }}
        >
-          <IconRightUpOutline16 size={15} />
+          <VscLinkExternal size={15} />
        </button>
      </div>
      {message !== null && <div className={css.browserMessage}>{message}</div>}
@@ -9,7 +9,7 @@
 * The parser is a pure function (`parseUnifiedDiff`) so the interesting
 * cases are unit-tested without a DOM.
 */
-import { useMemo, useState, type ReactNode } from 'react'
+import { useEffect, useMemo, useState, type ReactNode } from 'react'
 import clsx from 'clsx'
 import { t } from './locales.ts'
 import css from './sidebar.module.css'
@@ -171,6 +171,25 @@ function fileTag(file: DiffFile): string | null {
 /** Cap the flattened rows like DiffBlock: head + tail, expand button between. */
 const MAX_DIFF_ROWS = 500

+const TEST_PATH = /(^|\/)(?:__tests__|tests?|specs?|fixtures?|mocks?|snapshots?)(?:\/|$)|\.(?:test|spec)\.[^/]+$/i
+const DOC_PATH = /(^|\/)(?:docs?|documentation)(?:\/|$)|(^|\/)(?:readme|changelog|contributing|license|authors|notice)(?:\.[^/]*)?$/i
+const GENERATED_PATH = /(^|\/)(?:dist|build|coverage|generated|vendor|node_modules)(?:\/|$)|(^|\/)(?:package-lock\.json|pnpm-lock\.yaml|yarn\.lock|bun\.lockb?|composer\.lock|cargo\.lock|poetry\.lock)$/i
+const SOURCE_PATH = /\.(?:js|jsx|mjs|cjs|ts|tsx|mts|cts|py|pyw|rb|php|java|kt|kts|scala|go|rs|swift|c|h|cc|cpp|cxx|hpp|hh|hxx|cs|fs|fsx|vb|dart|lua|r|ex|exs|erl|hrl|clj|cljs|cljc|groovy|sh|bash|zsh|fish|ps1|sql|vue|svelte|astro|html|htm|css|scss|sass|less)$/i
+
+/** Source files open by default; tests, docs, generated files and unknown types stay folded. */
+function defaultExpandedFiles(files: DiffFile[]): Set<number> {
+  const expanded = new Set<number>()
+  files.forEach((file, index) => {
+    const path = displayPath(file.newPath === '/dev/null' ? file.oldPath : file.newPath)
+    if (!file.binary && file.hunks.length > 0
+      && !TEST_PATH.test(path) && !DOC_PATH.test(path) && !GENERATED_PATH.test(path)
+      && SOURCE_PATH.test(path)) {
+      expanded.add(index)
+    }
+  })
+  return expanded
+}
+
 export interface DiffViewProps {
  /** Unified diff text (`git.diff` or `git.commit-diff` payloads). */
  diff: string
@@ -187,22 +206,25 @@ export function DiffView({ diff, untrackedPath, untrackedContent }: DiffViewProp
    return parseUnifiedDiff(diff)
  }, [diff, untrackedPath, untrackedContent])
  const [expanded, setExpanded] = useState(false)
+  const [expandedFiles, setExpandedFiles] = useState<Set<number>>(() => defaultExpandedFiles(parsed.files))
+
+  useEffect(() => { setExpandedFiles(defaultExpandedFiles(parsed.files)) }, [parsed])

  // Flatten into display rows so the cap can slice a single list.
  const rows = useMemo(() => {
-    const out: Array<{ key: string; file: DiffFile; type: 'path' | 'hunk' | 'line'; hunk?: DiffHunk; line?: DiffLine }> = []
+    const out: Array<{ key: string; file: DiffFile; fileIndex: number; type: 'path' | 'hunk' | 'line'; hunk?: DiffHunk; line?: DiffLine }> = []
    parsed.files.forEach((file, fileIndex) => {
-      out.push({ key: `f${fileIndex}`, file, type: 'path' })
-      if (file.binary) return
+      out.push({ key: `f${fileIndex}`, file, fileIndex, type: 'path' })
+      if (file.binary || !expandedFiles.has(fileIndex)) return
      file.hunks.forEach((hunk, hunkIndex) => {
-        out.push({ key: `f${fileIndex}h${hunkIndex}`, file, type: 'hunk', hunk })
+        out.push({ key: `f${fileIndex}h${hunkIndex}`, file, fileIndex, type: 'hunk', hunk })
        hunk.lines.forEach((line, lineIndex) => {
-          out.push({ key: `f${fileIndex}h${hunkIndex}l${lineIndex}`, file, type: 'line', hunk, line })
+          out.push({ key: `f${fileIndex}h${hunkIndex}l${lineIndex}`, file, fileIndex, type: 'line', hunk, line })
        })
      })
    })
    return out
-  }, [parsed])
+  }, [parsed, expandedFiles])

  const hidden = rows.length - MAX_DIFF_ROWS
  const capped = hidden > 0 && !expanded
@@ -218,12 +240,29 @@ export function DiffView({ diff, untrackedPath, untrackedContent }: DiffViewProp
      const tag = fileTag(row.file)
      const from = displayPath(row.file.oldPath)
      const to = displayPath(row.file.newPath)
+      const expandable = !row.file.binary && row.file.hunks.length > 0
+      const fileExpanded = expandedFiles.has(row.fileIndex)
      return (
-        <div key={row.key} className={css.gitDiffFile}>
+        <button
+          key={row.key}
+          type="button"
+          className={css.gitDiffFile}
+          disabled={!expandable}
+          aria-expanded={expandable ? fileExpanded : undefined}
+          onClick={() => {
+            setExpandedFiles(current => {
+              const next = new Set(current)
+              if (next.has(row.fileIndex)) next.delete(row.fileIndex)
+              else next.add(row.fileIndex)
+              return next
+            })
+          }}
+        >
+          {expandable && <span aria-hidden="true" className={clsx(css.gitDiffFileChevron, fileExpanded && css.gitDiffFileChevronExpanded)}>›</span>}
          <span className={css.gitDiffFilePath}>{to}</span>
          {from !== to && <span className={css.gitDiffFileOld}>← {from}</span>}
          {tag !== null && <span className={css.gitDiffFileTag}>{tag}</span>}
-        </div>
+        </button>
      )
    }
    if (row.type === 'hunk') {
@@ -22,7 +22,7 @@
 * The strategy dispatch is pure (planFirstMatch / planFsReadOutcome in
 * editor-load.ts); this component only wires it to the host APIs.
 */
-import { useCallback, useEffect, useRef, useState, useSyncExternalStore } from 'react'
+import { useCallback, useEffect, useMemo, useRef, useState, useSyncExternalStore } from 'react'
 import { createElement } from 'react'
 import clsx from 'clsx'
 import { IconCheckOutline16, IconFolderOpen16 } from '@deepseek-ai/dsh-client-ui-primitives'
@@ -31,7 +31,10 @@ import { api, mediaUrl, type SessionScope } from './api.ts'
 import { BinaryDownload } from './binary-download.tsx'
 import { planFirstMatch, planFsReadOutcome, type EditorLoadAction } from './editor-load.ts'
 import { baseName } from './FileTree.tsx'
+import { createFrameBatcher } from './frame-batcher.ts'
 import { openSidebarFile } from './intercept.tsx'
+import { openWithSshActive, openWithUrl, parseOpenWithConfig, resolveOpenWithTargets } from './open-with.ts'
+import { updatePluginSettings } from './plugin-settings.ts'
 import { TreePanel } from './TreePanel.tsx'
 import { t } from './locales.ts'
 import { relativeTo } from './paths.ts'
@@ -51,6 +54,10 @@ const TREE_WIDTH_DEFAULT = 240
 const TREE_WIDTH_MIN = 160
 const TREE_WIDTH_MAX = 480

+/** Stable empty blob for the editor pluginSettings read (a fresh `?? {}`
+ *  would change identity every snapshot and loop useSyncExternalStore). */
+const EMPTY_PLUGIN_BLOB: Record<string, unknown> = {}
+
 /** The tab's persisted meta object (a malformed meta reads as empty). */
 function metaOf(tab: SidebarTab): Record<string, unknown> {
  return tab.meta !== null && typeof tab.meta === 'object' && !Array.isArray(tab.meta)
@@ -105,6 +112,16 @@ export function EditorHost(props: {
    useCallback((callback: () => void) => store.subscribe(callback), [store]),
    useCallback(() => store.getSnapshot().prefs.editorExplorer, [store]),
  )
+  // The file tree's "open with" configuration (pluginSettings['editor']): a
+  // blob subscription, so a pin click or a settings-page edit re-renders the
+  // menu immediately. The parsed config also drives which targets are shown
+  // (SSH mode hides the host-local ones).
+  const editorBlob = useSyncExternalStore(
+    useCallback((callback: () => void) => store.subscribe(callback), [store]),
+    useCallback(() => store.getSnapshot().prefs.pluginSettings['editor'] ?? EMPTY_PLUGIN_BLOB, [store]),
+  )
+  const openWithConfig = useMemo(() => parseOpenWithConfig(editorBlob.openWith), [editorBlob])
+  const openWithTargets = useMemo(() => resolveOpenWithTargets(openWithConfig), [openWithConfig])
  // A path-less tab shows the empty-state hint in merged mode — and in split
  // mode it is the standalone explorer (tree-only, see the render below).
  const showEmpty = path === ''
@@ -149,6 +166,39 @@ export function EditorHost(props: {
    })
  }

+  /** The context menu's "open with" action: reveal the path in the OS file
+   *  manager, or hand the target's URL (a local `file` URL, or the SSH-remote
+   *  form for VSCode-family editors in remote mode) to the host's external
+   *  opener. Failures are logged only — a missing handler is the OS's
+   *  dialog, not a sidebar error. */
+  const openWith = (targetId: string, absolute: string): void => {
+    const target = openWithTargets.find(item => item.id === targetId)
+    if (target === undefined) return
+    if (target.kind === 'reveal') {
+      void api.openExternal({ action: 'reveal', path: absolute }).catch(
+        (error: unknown) => { console.error('open external failed', error) },
+      )
+      return
+    }
+    const url = openWithUrl(target, absolute, openWithConfig)
+    if (url === undefined) return
+    void api.openExternal({ action: 'url', url }).catch(
+      (error: unknown) => { console.error('open external failed', error) },
+    )
+  }
+
+  /** Toggle one target's pinned state. The write is serialized (see
+   *  plugin-settings.ts) and the menu re-renders when the store prefs land. */
+  const toggleOpenWithPin = (targetId: string): void => {
+    updatePluginSettings(store, 'editor', (blob) => {
+      const config = parseOpenWithConfig(blob.openWith)
+      const pinned = config.pinned.includes(targetId)
+        ? config.pinned.filter(id => id !== targetId)
+        : [...config.pinned, targetId]
+      return { ...blob, openWith: { ...config, pinned } }
+    })
+  }
+
  // The viewer's toolbar, hoisted into THIS header: the text editor reports
  // its state and registers its commands (both null/absent for viewers
  // without a toolbar — image, pdf, binary download).
@@ -165,8 +215,16 @@ export function EditorHost(props: {
  // (no window listeners — the captured pointer keeps tracking even off the
  // handle). Local width while dragging, persisted into meta.treeWidth on
  // release. The panel docks right, so dragging LEFT widens it.
+  // Moves are BATCHED per frame (createFrameBatcher): applying every
+  // pointermove is a setState that re-renders this host AND the editor
+  // viewer below it (CodeMirror re-lays out on the width change) at event
+  // cadence — the visible drag lag on slower CPUs (#315). The batch applies
+  // the latest width once per frame; release flushes it and commits.
  const [dragWidth, setDragWidth] = useState<number | null>(null)
  const dragRef = useRef<{ startX: number; startWidth: number } | null>(null)
+  const pendingWidthRef = useRef(0)
+  const dragBatcher = useRef(createFrameBatcher()).current
+  useEffect(() => () => dragBatcher.dispose(), [dragBatcher])
  const treeWidth = dragWidth ?? treeWidthOf(tab)

  const onResizeStart = (event: React.PointerEvent): void => {
@@ -178,11 +236,17 @@ export function EditorHost(props: {
  const onResizeMove = (event: React.PointerEvent): void => {
    const drag = dragRef.current
    if (drag === null) return
-    setDragWidth(clampTreeWidth(drag.startWidth + (drag.startX - event.clientX)))
+    pendingWidthRef.current = clampTreeWidth(drag.startWidth + (drag.startX - event.clientX))
+    dragBatcher.schedule(() => setDragWidth(pendingWidthRef.current))
  }
  const onResizeEnd = (event: React.PointerEvent): void => {
    const drag = dragRef.current
    if (drag === null) return
+    // Flush the last pending frame (a release can land with the final move
+    // still queued; without the flush a stray frame would re-apply the
+    // drag width AFTER the null below). Both setStates batch into this same
+    // event, so the committed treeWidth wins visually.
+    dragBatcher.flushNow()
    dragRef.current = null
    setDragWidth(null)
    const finalWidth = clampTreeWidth(drag.startWidth + (drag.startX - event.clientX))
@@ -272,6 +336,11 @@ export function EditorHost(props: {
          onOpenFile={openFile}
          onOpenFileNewTab={openFileNewTab}
          onOpenFileSide={openFileSide}
+          openWithTargets={openWithTargets}
+          openWithPinned={openWithConfig.pinned}
+          openWithSsh={openWithSshActive(openWithConfig)}
+          onOpenWith={openWith}
+          onToggleOpenWithPin={toggleOpenWithPin}
          onReferenceFile={onReferenceFile}
        />
      </div>
@@ -365,6 +434,11 @@ export function EditorHost(props: {
              onOpenFile={openFile}
              onOpenFileNewTab={openFileNewTab}
              onOpenFileSide={openFileSide}
+              openWithTargets={openWithTargets}
+              openWithPinned={openWithConfig.pinned}
+              openWithSsh={openWithSshActive(openWithConfig)}
+              onOpenWith={openWith}
+              onToggleOpenWithPin={toggleOpenWithPin}
              onReferenceFile={onReferenceFile}
            />
          </div>
@@ -24,11 +24,14 @@ import { useCallback, useEffect, useRef, useState, type DragEvent, type MouseEve
 import { createPortal } from 'react-dom'
 import clsx from 'clsx'
 import {
-  IconCodeOutline16, IconCopyOutline16, IconDownloadOutline16, IconFolderClose16, IconFolderOpen16,
-  IconLinkOutline16, Menu, writeClipboard,
+  IconChevronRightOutline14, IconCodeOutline16, IconCopyOutline16, IconDownloadOutline16,
+  IconLinkOutline16, Menu, type MenuEntry, type MenuItem, writeClipboard,
 } from '@deepseek-ai/dsh-client-ui-primitives'
+import { SiCursor, SiZedindustries } from 'react-icons/si'
+import { VscFile, VscFolder, VscFolderOpened, VscLinkExternal, VscPin, VscPinned } from 'react-icons/vsc'
 import { api, downloadUrl, type FsEntry } from './api.ts'
-import { IconUploadOutline16 } from './icons.tsx'
+import { IconUploadOutline16, IconVscode16 } from './icons.tsx'
+import type { OpenWithTarget } from './open-with.ts'
 import { relativeTo } from './paths.ts'
 import { t } from './locales.ts'
 import { uploadItemsFromDrop, uploadItemsFromFiles, type UploadItem } from './upload.ts'
@@ -109,6 +112,19 @@ export function FileTree(props: {
  onOpenFileNewTab?: (path: string) => void
  /** Context-menu "open to the side" (file rows; absent → no entry). */
  onOpenFileSide?: (path: string) => void
+  /**
+   * The "open with" menu: resolved external targets (already SSH-filtered
+   * and in menu order). Absent → the whole section is hidden.
+   */
+  openWithTargets?: OpenWithTarget[]
+  /** Ids of targets pinned to the menu's top level (subset of the ids). */
+  openWithPinned?: string[]
+  /** Whether the workspace is remote (appends the SSH hint to target labels). */
+  openWithSsh?: boolean
+  /** Open one target externally (reveal or URL — the caller decides). */
+  onOpenWith?: (targetId: string, path: string) => void
+  /** Toggle one target's pinned state (the submenu row's pushpin). */
+  onToggleOpenWithPin?: (targetId: string) => void
  /** Insert `@<relative path>` into the composer draft. */
  onReferenceFile: (path: string) => void
  /** Bump to wipe the level cache and reload the visible set. */
@@ -118,7 +134,7 @@ export function FileTree(props: {
  /** True while an upload is in flight (drops are ignored). */
  busy: boolean
 }) {
-  const { sessionId, cwd, expanded, onToggle, onOpenFile, onOpenFileNewTab, onOpenFileSide, onReferenceFile, refreshTick, onUploadRequest, busy } = props
+  const { sessionId, cwd, expanded, onToggle, onOpenFile, onOpenFileNewTab, onOpenFileSide, openWithTargets, openWithPinned, openWithSsh, onOpenWith, onToggleOpenWithPin, onReferenceFile, refreshTick, onUploadRequest, busy } = props
  const [data, setData] = useState<Record<string, LevelData>>({})
  const dataRef = useRef(data)
  /** The row whose path was just copied ("copied" label replaces its button). */
@@ -307,6 +323,88 @@ export function FileTree(props: {
    anchor.remove()
  }

+  /** The menu label of one open target: a locale key for the built-ins, the
+   *  user's own name for custom editors, plus the SSH hint in remote mode. */
+  const openWithLabelOf = (target: OpenWithTarget): string => {
+    const name = target.nameKey !== undefined ? t(target.nameKey) : target.name
+    return openWithSsh === true && !target.localOnly ? `${name}${t('openWithSshSuffix')}` : name
+  }
+
+  /**
+   * The "open with" menu entries: the pinned targets as DIRECT rows, then
+   * the parent row with every target as a nested submenu. Both only render
+   * when the caller wired the feature and at least one target is visible.
+   */
+  const openWithEntries = (): MenuEntry[] => {
+    if (openWithTargets === undefined || onOpenWith === undefined || openWithTargets.length === 0) return []
+    const pinnedIds = openWithPinned ?? []
+    /** Brand marks for the built-ins (monochrome silhouettes, currentColor);
+     *  reveal gets the folder glyph, custom editors a generic code mark. */
+    const itemIcon = (target: OpenWithTarget): ReactNode => {
+      if (target.kind === 'reveal') return <VscFolderOpened size={16} />
+      if (target.id === 'vscode') return <IconVscode16 size={16} />
+      if (target.id === 'cursor') return <SiCursor size={16} />
+      if (target.id === 'zed') return <SiZedindustries size={16} />
+      return <IconCodeOutline16 size={16} />
+    }
+    const pinned = openWithTargets
+      .filter(target => pinnedIds.includes(target.id))
+      .map<MenuItem>(target => ({
+        id: `open-with:${target.id}`,
+        label: openWithLabelOf(target),
+        icon: itemIcon(target),
+      }))
+    const submenu = openWithTargets.map<MenuItem>(target => {
+      const pinnedNow = pinnedIds.includes(target.id)
+      return {
+        id: `open-with:${target.id}`,
+        label: (
+          <span className={css.openWithLabel}>
+            <span className={css.openWithName}>{openWithLabelOf(target)}</span>
+            {/* The pushpin: a span (never a button — the Menu row itself is
+                a button, so a nested interactive element would be invalid).
+                Clicking it pins/unpins the target at the menu's top level
+                WITHOUT selecting the row: the pin stops propagation, so the
+                menu stays open and the icon flips on the next render. */}
+            <span
+              role="button"
+              tabIndex={-1}
+              className={clsx(css.openWithPin, pinnedNow && css.openWithPinActive)}
+              aria-label={pinnedNow ? t('unpinOpenWith') : t('pinOpenWith')}
+              title={pinnedNow ? t('unpinOpenWith') : t('pinOpenWith')}
+              onClick={(event) => {
+                event.preventDefault()
+                event.stopPropagation()
+                onToggleOpenWithPin?.(target.id)
+              }}
+            >
+              {pinnedNow ? <VscPinned size={14} /> : <VscPin size={14} />}
+            </span>
+          </span>
+        ),
+        icon: itemIcon(target),
+      }
+    })
+    return [
+      ...pinned,
+      ...(pinned.length > 0 ? [{ id: 'open-with-sep', type: 'separator' } as MenuEntry] : []),
+      {
+        id: 'open-with-menu',
+        // The primitives Menu renders no chevron for submenu parents — the
+        // trailing arrow is supplied inside the label (full-width flex row,
+        // right-aligned), matching how the submenu rows right-align the pin.
+        label: (
+          <span className={css.openWithLabel}>
+            <span className={css.openWithName}>{t('openWithMenu')}</span>
+            <IconChevronRightOutline14 size={14} className={css.openWithChevron} aria-hidden />
+          </span>
+        ),
+        icon: <VscLinkExternal size={16} />,
+        submenu,
+      },
+    ]
+  }
+
  const root = cwd

  const renderLevel = (dir: string, depth: number): ReactNode => {
@@ -346,7 +444,7 @@ export function FileTree(props: {
              onDrop={(event) => { handleDirDrop(event, entry.path) }}
              onContextMenu={(event) => { openRowMenu(event, entry.path, true) }}
            >
-              {isOpen ? <IconFolderOpen16 size={14} /> : <IconFolderClose16 size={14} />}
+              {isOpen ? <VscFolderOpened size={14} /> : <VscFolder size={14} />}
              <span className={css.explorerName}>{entry.name}</span>
              {entry.isSymlink && <IconLinkOutline16 size={12} className={css.explorerSymlink} />}
              {rowActions(entry)}
@@ -377,7 +475,7 @@ export function FileTree(props: {
          onDrop={(event) => { handleFileDrop(event, entry.path) }}
          onContextMenu={(event) => { openRowMenu(event, entry.path, false) }}
        >
-          <IconCodeOutline16 size={14} />
+          <VscFile size={14} />
          <span className={css.explorerName}>{entry.name}</span>
          {entry.isSymlink && <IconLinkOutline16 size={12} className={css.explorerSymlink} />}
          {rowActions(entry)}
@@ -406,7 +504,7 @@ export function FileTree(props: {
            onDrop={(event) => { handleDirDrop(event, root) }}
            onContextMenu={(event) => { openRowMenu(event, root, true) }}
          >
-            <IconFolderOpen16 size={14} />
+            <VscFolderOpened size={14} />
            <span className={css.explorerName}>{baseName(root)}</span>
            {copiedPath === root
              ? <span className={css.explorerCopied}>{t('copied')}</span>
@@ -498,21 +596,22 @@ export function FileTree(props: {
        items={[
          // The open escapes head the FILE menu (dirs only get copy).
          ...(rowMenu?.isDir === false && onOpenFileNewTab !== undefined
-            ? [{ id: 'open-new-tab', label: t('openFileNewTab'), icon: <IconCodeOutline16 size={14} /> }]
+            ? [{ id: 'open-new-tab', label: t('openFileNewTab'), icon: <IconCodeOutline16 size={16} /> }]
            : []),
          ...(rowMenu?.isDir === false && onOpenFileSide !== undefined
-            ? [{ id: 'open-side', label: t('openFileSide'), icon: <IconFolderOpen16 size={14} /> }]
+            ? [{ id: 'open-side', label: t('openFileSide'), icon: <VscFolderOpened size={16} /> }]
            : []),
+          ...openWithEntries(),
          // Download applies to files only (the host route refuses directories).
          ...(rowMenu?.isDir === false
-            ? [{ id: 'download', label: t('download'), icon: <IconDownloadOutline16 size={14} /> }]
+            ? [{ id: 'download', label: t('download'), icon: <IconDownloadOutline16 size={16} /> }]
            : []),
          // Upload into a directory (incl. the workspace root row).
          ...(rowMenu?.isDir === true
-            ? [{ id: 'upload-here', label: t('uploadHere'), icon: <IconUploadOutline16 size={14} /> }]
+            ? [{ id: 'upload-here', label: t('uploadHere'), icon: <IconUploadOutline16 size={16} /> }]
            : []),
-          { id: 'relative', label: t('copyRelative'), icon: <IconCopyOutline16 size={14} /> },
-          { id: 'absolute', label: t('copyAbsolute'), icon: <IconCopyOutline16 size={14} /> },
+          { id: 'relative', label: t('copyRelative'), icon: <IconCopyOutline16 size={16} /> },
+          { id: 'absolute', label: t('copyAbsolute'), icon: <IconCopyOutline16 size={16} /> },
        ]}
        onSelect={(id) => {
          const target = rowMenu
@@ -526,6 +625,10 @@ export function FileTree(props: {
            onOpenFileSide?.(target.path)
            return
          }
+          if (id.startsWith('open-with:')) {
+            onOpenWith?.(id.slice('open-with:'.length), target.path)
+            return
+          }
          if (id === 'download') {
            downloadFile(target.path)
            return
@@ -893,3 +893,68 @@
  color: var(--dsw-alias-label-secondary);
  padding: 2px 2px 0;
 }
+
+/* Open-with settings panel: one custom editor row (name + URL template +
+   VSCode-family checkbox + remove) and the row-validity hint. */
+.openWithEditorRow {
+  display: grid;
+  grid-template-columns: 1fr 1.5fr auto auto;
+  gap: 8px;
+  align-items: center;
+  min-width: 0;
+}
+
+.openWithEditorInput,
+.openWithEditorTemplate {
+  width: 100%;
+  min-width: 0;
+  box-sizing: border-box;
+  padding: 5px 8px;
+  border: 1px solid var(--dsw-alias-border-l2);
+  border-radius: 8px;
+  background: var(--dsw-alias-bg-layer-3);
+  color: var(--dsw-alias-label-primary);
+  font: inherit;
+  font-size: 13px;
+  line-height: 20px;
+}
+
+.openWithEditorInput:focus-visible,
+.openWithEditorTemplate:focus-visible {
+  outline: 2px solid var(--dsw-alias-state-business-primary);
+  outline-offset: 1px;
+}
+
+.openWithFamily {
+  display: inline-flex;
+  align-items: center;
+  gap: 5px;
+  font-size: 12px;
+  color: var(--dsw-alias-label-secondary);
+  white-space: nowrap;
+  cursor: pointer;
+}
+
+.openWithRemove {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: 4px;
+  border: none;
+  border-radius: 8px;
+  background: none;
+  color: var(--dsw-alias-label-tertiary);
+  cursor: pointer;
+}
+
+.openWithRemove:hover {
+  color: var(--dsw-alias-state-error-primary);
+  background: var(--dsw-alias-bg-layer-2);
+}
+
+.openWithHint {
+  font-size: 12px;
+  line-height: 17px;
+  color: var(--dsw-alias-state-error-primary);
+  padding: 0 2px;
+}
@@ -492,12 +492,13 @@ function SelectRow(props: {

 /**
 * The secondary settings popup body of one feature (tab or viewer):
- * - `settings.render` (custom panel) when declared — rendered with the
- *   shared store/service, the live prefs, the descriptor's own plugin
- *   settings blob, a persistence helper, and a close callback;
- * - otherwise the host-prefs `toggles` rows, then the plugin-owned
- *   `pluginToggles` rows (their values live in `pluginSettings[feature.id]`,
- *   projected onto the prefs face so the shared row renderer reads them).
+ * - the host-prefs `toggles` rows, then the plugin-owned `pluginToggles`
+ *   rows (their values live in `pluginSettings[feature.id]`, projected onto
+ *   the prefs face so the shared row renderer reads them);
+ * - `settings.render` (custom panel) AFTER those rows when declared — the
+ *   custom panel is an extension of the row list, not a replacement, so a
+ *   feature can keep its declarative rows (e.g. the editor's
+ *   open-behavior picker) and still ship a custom configuration area.
 */
 export function SettingsBody(props: {
  feature: TabDescriptor | FileViewerDescriptor
@@ -515,48 +516,50 @@ export function SettingsBody(props: {
 }) {
  const { feature, prefs, store, service, onToggle, onCommit, onSelectValue, onPluginToggle, onPluginCommit, onPluginSelectValue, onPluginWrite, onClose } = props
  const render = feature.settings?.render
-  if (render !== undefined) {
-    return (
-      <SettingsRender
-        render={render}
-        renderProps={{
-          store,
-          service,
-          prefs,
-          pluginSettings: prefs.pluginSettings[feature.id] ?? {},
-          updatePluginSetting: onPluginWrite,
-          close: onClose,
-        }}
-      />
-    )
-  }
  const toggles = feature.settings?.toggles ?? []
  const pluginToggles = feature.settings?.pluginToggles ?? []
-  if (toggles.length === 0 && pluginToggles.length === 0) return null
+  if (render === undefined && toggles.length === 0 && pluginToggles.length === 0) return null
  // Plugin rows read their values from the descriptor's OWN blob through
  // an explicit value source — no projection onto the prefs face, so a
  // plugin key can never collide with (or silently read) a host pref of
  // the same name.
  const pluginBlob = prefs.pluginSettings[feature.id] ?? {}
  return (
-    <div className={css.popupRows}>
-      {toggles.length > 0 && (
-        <FeatureSettingsRows
-          toggles={toggles}
-          prefs={prefs}
-          onToggle={onToggle}
-          onCommit={onCommit}
-          onSelectValue={onSelectValue}
-        />
+    <div>
+      {(toggles.length > 0 || pluginToggles.length > 0) && (
+        <div className={css.popupRows}>
+          {toggles.length > 0 && (
+            <FeatureSettingsRows
+              toggles={toggles}
+              prefs={prefs}
+              onToggle={onToggle}
+              onCommit={onCommit}
+              onSelectValue={onSelectValue}
+            />
+          )}
+          {pluginToggles.length > 0 && (
+            <FeatureSettingsRows
+              toggles={pluginToggles}
+              prefs={prefs}
+              onToggle={onPluginToggle}
+              onCommit={onPluginCommit}
+              onSelectValue={onPluginSelectValue}
+              valueSource={(key) => pluginBlob[key]}
+            />
+          )}
+        </div>
      )}
-      {pluginToggles.length > 0 && (
-        <FeatureSettingsRows
-          toggles={pluginToggles}
-          prefs={prefs}
-          onToggle={onPluginToggle}
-          onCommit={onPluginCommit}
-          onSelectValue={onPluginSelectValue}
-          valueSource={(key) => pluginBlob[key]}
+      {render !== undefined && (
+        <SettingsRender
+          render={render}
+          renderProps={{
+            store,
+            service,
+            prefs,
+            pluginSettings: prefs.pluginSettings[feature.id] ?? {},
+            updatePluginSetting: onPluginWrite,
+            close: onClose,
+          }}
        />
      )}
    </div>
@@ -1045,9 +1048,9 @@ export function SideCardSection({ store, service }: SideCardSectionProps) {
          feature is open — the Modal primitive runs hooks unconditionally,
          so a closed-but-mounted Modal would break SSR (and the
          renderToString spec) under the test dual-react split.
-          Content: `settings.render` (custom panel) when declared, else the
-          host-prefs `toggles` rows followed by the plugin-owned
-          `pluginToggles` rows (their values live in pluginSettings[id]). */}
+          Content: the host-prefs `toggles` rows, the plugin-owned
+          `pluginToggles` rows (their values live in pluginSettings[id]),
+          then the custom `settings.render` panel when declared. */}
      {settingsFor !== null && (
        <Modal
          open
@@ -28,7 +28,7 @@
 * drawer floats). Widening does not migrate back: the tabs keep living in
 * the right tree.
 */
-import { createElement, useCallback, useEffect, useMemo, useRef, useState, type DragEvent, type ReactNode } from 'react'
+import { createElement, memo, useCallback, useEffect, useMemo, useRef, useState, type DragEvent, type ReactNode } from 'react'
 import { useSyncExternalStore } from 'react'
 import clsx from 'clsx'
 import { IconCloseFill14, Tooltip } from '@deepseek-ai/dsh-client-ui-primitives'
@@ -52,6 +52,7 @@ import type { TabDragPayload } from './TabBar.tsx'
 import { relativeTo } from './paths.ts'
 import { OrphanedTab } from './OrphanedTab.tsx'
 import { RenderBoundary } from './RenderBoundary.tsx'
+import { tabContentCompare, type TabContentMemoKey } from './tab-content-memo.ts'
 import { detectNewDirectSubagent } from './subagent-detect.ts'
 import { detectNewJob } from './subagent-jobs.ts'
 import { t } from './locales.ts'
@@ -113,23 +114,25 @@ function injectUserCss(attr: string, id: string, cssText: string): HTMLStyleElem
  return tag
 }

-/** Render the content of one tab (dispatched by type). */
-function TabContent(props: {
-  tab: SidebarTab
-  sessionId: string
-  cwd: string | undefined
-  expanded: string[]
+/** Props of one tab's content cell = the memo key (tab-content-memo.ts) plus
+ *  the runtime objects/callbacks the cell renders with. The memo comparator
+ *  is the pure `tabContentCompare`; anything in the key decides a re-render
+ *  must propagate, anything outside it must be a stable object (ctx/store)
+ *  or covered by a compared field (paneId covers onOpenDiff's captured
+ *  pane; sessionId/cwd cover onReferenceFile). */
+interface TabContentProps extends TabContentMemoKey {
  onToggleDir: (path: string) => void
  onReferenceFile: (path: string) => void
  ctx: Context
  store: SidebarStore
-  /** Whether this tab is the active one AND the panel is open (live views pause otherwise). */
-  visible: boolean
  /** Fired before a topology node jumps to its child session (see Sidebar). */
  onSubagentJump: (childSessionId: string) => void
  /** Open a diff tab from the git panel (placement handled by the store). */
  onOpenDiff: (tab: SidebarTab) => void
-}) {
+}
+
+/** Render the content of one tab (dispatched by type). */
+const TabContent = memo(function TabContent(props: TabContentProps) {
  const { tab, sessionId, cwd, expanded, onToggleDir, onReferenceFile, ctx, store, visible, onSubagentJump, onOpenDiff } = props
  const scope = { sessionId, cwd }
  const descriptor = ctx.betterSidebar?.getTab(tab.type)
@@ -152,7 +155,7 @@ function TabContent(props: {
      onToggleDir, onReferenceFile, onOpenDiff, onSubagentJump,
    }),
  )
-}
+}, tabContentCompare)

 /** The + menu options for the current state, driven by the tab registry.
 * Hidden tabs (editor/diff) never show; `available` returning false shows
@@ -185,6 +188,18 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
  )
  void localeRevision

+  // Tab-registry revision: TabContent memo cells must pick up a descriptor
+  // a plugin registers/disposes after mount (the + menu / icons already read
+  // the registry at render). Rare events (plugin (un)mount), so one full
+  // re-render per change is fine — this is what keeps the memoized cells
+  // from going stale, mirroring the localeRevision mechanism above.
+  const [tabsVersion, setTabsVersion] = useState(0)
+  useEffect(() => {
+    const service = ctx.betterSidebar
+    if (service === undefined) return
+    return service.subscribe(() => setTabsVersion(version => version + 1))
+  }, [ctx])
+
  // Narrow (mobile) viewports collapse the two panels into one: the right
  // panel becomes a full-width drawer holding BOTH workbenches, the bottom
  // panel (and its toggle button) disappears, and the layout push is
@@ -497,7 +512,16 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
  // horizontal edges — including the animated margin-right push while the
  // right panel opens/closes; a frame that never appears keeps the initial
  // zero-size fallback (the panel renders at 0 width until measured).
-  const [centerRect, setCenterRect] = useState({ left: 0, right: 0 })
+  // The rect lives in a REF (not state): the open/close transition resizes
+  // the center column EVERY frame for its duration, and reacting per frame
+  // with setState re-renders the whole Sidebar (every mounted tab) at
+  // animation cadence — the visible toggle jank (#315). measureCenter
+  // writes the bottom panel's edges directly (same DOM-write pattern as
+  // applyDrag), so the panel still tracks the column per frame with zero
+  // React work; `centerMeasured` flips ONCE to gate the hidden→visible
+  // first-paint fallback.
+  const centerRectRef = useRef({ left: 0, right: 0 })
+  const [centerMeasured, setCenterMeasured] = useState(false)
  // Refs keep the measure step stable across renders and let it skip work
  // mid-drag: during a width/corner drag the layout push resizes the center
  // column every frame, and reacting (setCenterRect → re-render) would
@@ -518,13 +542,18 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
      return
    }
    const rect = col.getBoundingClientRect()
-    // The bottom panel only cares about the horizontal edges: a pure height
-    // change (the bottom panel itself opening/closing) must not re-render,
-    // so keep the previous object when left/right are unchanged.
-    setCenterRect(prev =>
-      prev.left === rect.left && prev.right === rect.right
-        ? prev
-        : { left: rect.left, right: rect.right })
+    // Ref + direct DOM write (see the centerRectRef comment): the bottom
+    // panel keeps tracking the center column per frame during the right
+    // panel's open/close animation without re-rendering the shell. The
+    // one-shot measured flip renders the panel visible once (a stale
+    // {0,0} fallback would flash full-width).
+    centerRectRef.current = { left: rect.left, right: rect.right }
+    const bottom = bottomRef.current
+    if (bottom !== null) {
+      bottom.style.setProperty('left', `${rect.left}px`)
+      bottom.style.setProperty('right', `${window.innerWidth - rect.right}px`)
+    }
+    setCenterMeasured(prev => (prev ? prev : true))
  }, [])
  useEffect(() => {
    let disposed = false
@@ -571,6 +600,13 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
    let locateFrame: number | null = null
    const scheduleLocate = (): void => {
      if (locateFrame !== null) return
+      // Mid-drag every frame writes --dsh-sidebar-* on <html>'s style
+      // attribute, which is the mutation this watcher observes — relocating
+      // per drag frame is pointless (the center column node cannot change
+      // while the pointer is captured) and adds a querySelector to every
+      // frame's budget (#315). The 1.5s retry below still covers any node
+      // swap that somehow lands mid-drag.
+      if (draggingRef.current) return
      locateFrame = requestAnimationFrame(() => {
        locateFrame = null
        locate()
@@ -708,7 +744,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
    // width (innerWidth - state.width - detailsWidth), so this equals
    // `width + detailsWidth` — derived from the measured column, keeping the
    // drag write-only (no React re-render mid-drag).
-    bottomRef.current?.style.setProperty('right', `${(window.innerWidth - centerRect.right) + (width - (state?.width ?? 0))}px`)
+    bottomRef.current?.style.setProperty('right', `${(window.innerWidth - centerRectRef.current.right) + (width - (state?.width ?? 0))}px`)
    writeGeometry(width, height)
  }

@@ -1033,6 +1069,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
  const renderTab = (tab: SidebarTab, active: boolean, paneId: string, bottom = false) => (
    <TabContent
      tab={tab}
+      paneId={paneId}
      sessionId={sessionId}
      cwd={cwd}
      expanded={state.expanded}
@@ -1043,6 +1080,8 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
      visible={bottom ? state.bottomOpen && active : state.panelOpen && active}
      onSubagentJump={(childSessionId) => { subagentJumpRef.current = childSessionId }}
      onOpenDiff={(diffTab) => { store.reduce(s => openDiffTab(s, paneId, diffTab)) }}
+      localeRevision={localeRevision}
+      tabsVersion={tabsVersion}
    />
  )

@@ -1231,7 +1270,7 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
        data-dsh-bottom-panel
        style={{
          height: Math.min(state.bottomHeight, window.innerHeight),
-          left: centerRect.left,
+          left: centerRectRef.current.left,
          // Keep the panel above the on-screen keyboard when the visual
          // viewport shrinks (see the keyboardInset effect).
          bottom: keyboardInset > 0 ? `${keyboardInset}px` : undefined,
@@ -1240,14 +1279,14 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
          // details column's left edge (the details column sits between the
          // center and the right panel, and the right panel's margin-right
          // push is already baked into centerRect.right).
-          right: window.innerWidth - centerRect.right,
+          right: window.innerWidth - centerRectRef.current.right,
          // The seam against the open right panel needs its own hairline
          // (the right panel's border-left alone is covered by this panel's
          // fill — without it the corner looks cut off).
          borderRight: state.panelOpen ? '1px solid var(--dsw-alias-border-l2)' : undefined,
          // Unmeasured center column → keep the panel invisible (zero-size
          // geometry would flash full-width overflow instead).
-          visibility: centerRect.right > 0 ? undefined : 'hidden',
+          visibility: centerMeasured ? undefined : 'hidden',
        }}
       
        data-dragging={(draggingBottom || draggingCorner) || undefined}
@@ -3,7 +3,9 @@
 * overflow scrolls horizontally, a close button per tab, a four-way split
 * button cluster, and the + menu that opens new tabs (explorer / git /
 * terminal). Tabs are draggable; dropping onto another tab inserts before it,
- * dropping on the strip background appends to this pane.
+ * dropping on the strip background appends to this pane. Right-clicking a
+ * tab opens the tab context menu (close / close others / close to the left /
+ * close to the right, all scoped to this pane).
 */
 import { useEffect, useRef, useState, type ReactNode } from 'react'
 import clsx from 'clsx'
@@ -71,8 +73,14 @@ export function TabBar(props: {
    paneId, tabs, active, onActivate, onClose, onNewTab, newTabOptions, onDropTab, getTabIcon, getTabBadge,
  } = props
  const [menuOpen, setMenuOpen] = useState(false)
+  // The tab right-click context menu: the target tab plus the cursor
+  // position (the portaled Menu anchors there, following GitView/FileTree).
+  const [tabMenu, setTabMenu] = useState<{ tabId: string; x: number; y: number } | null>(null)
  const [dragOver, setDragOver] = useState(false)
  const listRef = useRef<HTMLDivElement>(null)
+  // The context target's index in the render-time tab snapshot; -1 when the
+  // tab disappeared since the menu opened (the menu hides then).
+  const tabMenuIndex = tabMenu === null ? -1 : tabs.findIndex(tab => tab.id === tabMenu.tabId)

  // Middle-click close: the press target is recorded on middle mousedown
  // (preventDefaulted to disarm Chrome's middle-click autoscroll — its
@@ -194,6 +202,14 @@ export function TabBar(props: {
                middlePressed.current = { id: tab.id, node: event.currentTarget }
              }
            }}
+            onContextMenu={(event) => {
+              // Take over the browser menu: the tab context menu offers the
+              // close operations for this pane. Opening it also dismisses
+              // the + menu (only one menu at a time).
+              event.preventDefault()
+              setMenuOpen(false)
+              setTabMenu({ tabId: tab.id, x: event.clientX, y: event.clientY })
+            }}
          >
            {getTabIcon?.(tab) ?? null}
            {getTabBadge?.(tab) ?? null}
@@ -237,12 +253,52 @@ export function TabBar(props: {
              className={css.tabBarPlus}
              aria-label={t('newTab')}
              title={t('newTab')}
-              onClick={() => { setMenuOpen(v => !v) }}
+              onClick={() => { setMenuOpen(v => !v); setTabMenu(null) }}
            >
              <IconPlusOutline16 />
            </button>
          )}
        />
+        {/*
+          The tab context menu, positioned at the right-click cursor (portal
+          so the panel's overflow clip cannot crop it). Close operations are
+          scoped to THIS pane: "close others/left/right" walk the render-time
+          tab snapshot and reuse the per-tab onClose path (which routes
+          through the service and releases terminals), so the target tab is
+          never closed and the pane never empties mid-loop.
+        */}
+        <Menu
+          open={tabMenu !== null && tabMenuIndex >= 0}
+          onClose={() => { setTabMenu(null) }}
+          items={[
+            { id: 'close', label: t('close') },
+            { id: 'closeOthers', label: t('closeOtherTabs'), ...(tabs.length <= 1 ? { disabled: true } : {}) },
+            { id: 'closeLeft', label: t('closeLeftTabs'), ...(tabMenuIndex <= 0 ? { disabled: true } : {}) },
+            { id: 'closeRight', label: t('closeRightTabs'), ...(tabMenuIndex >= tabs.length - 1 ? { disabled: true } : {}) },
+          ]}
+          onSelect={(id) => {
+            const target = tabMenu
+            if (target === null) return
+            setTabMenu(null)
+            const index = tabs.findIndex(tab => tab.id === target.tabId)
+            if (index < 0) return
+            if (id === 'close') {
+              onClose(target.tabId)
+            } else if (id === 'closeOthers') {
+              for (const tab of tabs) {
+                if (tab.id !== target.tabId) onClose(tab.id)
+              }
+            } else if (id === 'closeLeft') {
+              for (const tab of tabs.slice(0, index)) onClose(tab.id)
+            } else if (id === 'closeRight') {
+              for (const tab of tabs.slice(index + 1)) onClose(tab.id)
+            }
+          }}
+          portal
+          align="start"
+          getAnchorRect={() => (tabMenu === null ? null : new DOMRect(tabMenu.x, tabMenu.y, 0, 0))}
+          anchor={<span />}
+        />
      </div>
    </div>
  )
@@ -21,6 +21,7 @@ import { IconFolderOpen16, IconRefreshOutline16 } from '@deepseek-ai/dsh-client-
 import { api } from './api.ts'
 import { FileTree } from './FileTree.tsx'
 import { IconUploadOutline16 } from './icons.tsx'
+import type { OpenWithTarget } from './open-with.ts'
 import { t } from './locales.ts'
 import { resolveSidebarPath } from './produced-files.ts'
 import { UploadOverlay } from './UploadOverlay.tsx'
@@ -50,12 +51,19 @@ export function TreePanel(props: {
  onOpenFileNewTab?: (path: string) => void
  /** File context-menu "open to the side" (passed through to FileTree). */
  onOpenFileSide?: (path: string) => void
+  /** The "open with" menu surface (passed through to FileTree; absent →
+   *  the whole section is hidden). */
+  openWithTargets?: OpenWithTarget[]
+  openWithPinned?: string[]
+  openWithSsh?: boolean
+  onOpenWith?: (targetId: string, path: string) => void
+  onToggleOpenWithPin?: (targetId: string) => void
  onReferenceFile: (path: string) => void
  /** Full-window presentation: the panel fills its host instead of docking
   *  at a fixed width. */
  full?: boolean
 }) {
-  const { sessionId, cwd, expanded, onToggle, onOpenFile, onOpenFileNewTab, onOpenFileSide, onReferenceFile, full } = props
+  const { sessionId, cwd, expanded, onToggle, onOpenFile, onOpenFileNewTab, onOpenFileSide, openWithTargets, openWithPinned, openWithSsh, onOpenWith, onToggleOpenWithPin, onReferenceFile, full } = props
  const [query, setQuery] = useState('')
  const [results, setResults] = useState<{ matches: string[]; truncated: boolean } | null>(null)
  const [error, setError] = useState<string | null>(null)
@@ -217,6 +225,11 @@ export function TreePanel(props: {
          onOpenFile={onOpenFile}
          onOpenFileNewTab={onOpenFileNewTab}
          onOpenFileSide={onOpenFileSide}
+          openWithTargets={openWithTargets}
+          openWithPinned={openWithPinned}
+          openWithSsh={openWithSsh}
+          onOpenWith={onOpenWith}
+          onToggleOpenWithPin={onToggleOpenWithPin}
          onReferenceFile={onReferenceFile}
          refreshTick={refreshTick}
          onUploadRequest={startUpload}
@@ -289,6 +289,12 @@ export const api = {
   *  check; see the host's browser.probe route). */
  browserProbe: (url: string, signal?: AbortSignal) =>
    call<BrowserProbeResult>('browser.probe', { url }, signal),
+  /** External open for the file tree's "open with" menu: reveal a path in
+   *  the OS file manager, or hand a custom-scheme URL (vscode://, cursor://,
+   *  zed://, custom editors) to its registered handler. The host launches
+   *  the platform opener (argv, no shell). */
+  openExternal: (payload: { action: 'reveal'; path: string } | { action: 'url'; url: string }) =>
+    call<{ started: boolean }>('open.external', payload),
 }

 /** Absolute URL of the media route for one path (images only). */
@@ -13,6 +13,7 @@ import { allLeaves, isAgentTabId, type SidebarState } from '../state.ts'
 import { t } from '../locales.ts'
 import { openSidebarFile } from '../intercept.tsx'
 import { EditorHost } from '../EditorHost.tsx'
+import { OpenWithSettings } from '../open-with-settings.tsx'
 import { lazyChunkComponent } from '../lazy-chunk.tsx'
 import { GitView } from '../GitView.tsx'
 import { DiffTab } from '../DiffTab.tsx'
@@ -90,7 +91,9 @@ export function builtinTabs(ctx: Context, options: BuiltinTabOptions = {}): read
      dedupeKey: (tab) => tab.path,
      // Declarative settings: the file-open behavior picker (in-place switch
      // vs per-path windows) renders as an iconed select row under the
-      // editor card's gear in the Side card settings page.
+      // editor card's gear in the Side card settings page; the "open with"
+      // configuration (SSH host + custom editors) is the custom panel BELOW
+      // those rows — the settings seam renders rows first, custom panel after.
      settings: {
        toggles: [{
          key: 'editorExplorer',
@@ -112,6 +115,9 @@ export function builtinTabs(ctx: Context, options: BuiltinTabOptions = {}): read
            },
          ],
        }],
+        render: ({ pluginSettings, updatePluginSetting }) => (
+          <OpenWithSettings pluginSettings={pluginSettings} updatePluginSetting={updatePluginSetting} />
+        ),
      },
      component: ({ ctx, store, scope, tab, expanded, onToggleDir, onReferenceFile }) => (
        <EditorHost
@@ -0,0 +1,56 @@
+/**
+ * Per-frame task coalescing for pointer-driven interactions.
+ *
+ * Pointer streams fire several times faster than the display refresh, and
+ * applying every event (a React setState, a store reduce) re-renders whole
+ * trees at event cadence — the visible drag lag on slower CPUs (#315). This
+ * batcher keeps the LATEST scheduled task, runs it at most once per
+ * animation frame, and lets the caller flush synchronously on release (so
+ * the final pointer position is never lost to a cancelled frame).
+ *
+ * Callers compose the pending value in a ref before scheduling; the
+ * scheduled task reads that ref, so replacing the task on every event is
+ * cheap (one ref write + one rAF check).
+ */
+export interface FrameBatcher {
+  /** Schedule (or replace) the per-frame task. Safe to call on every event. */
+  schedule(task: () => void): void
+  /** Cancel any pending frame and run the scheduled task synchronously
+   *  (no-op when nothing is scheduled). */
+  flushNow(): void
+  /** Cancel any pending frame and drop the task without running it. */
+  dispose(): void
+}
+
+export function createFrameBatcher(): FrameBatcher {
+  let frame: number | null = null
+  let task: (() => void) | null = null
+
+  const run = (): void => {
+    frame = null
+    const current = task
+    task = null
+    current?.()
+  }
+
+  return {
+    schedule(next) {
+      task = next
+      if (frame === null) frame = requestAnimationFrame(run)
+    },
+    flushNow() {
+      if (frame !== null) {
+        cancelAnimationFrame(frame)
+        frame = null
+      }
+      run()
+    },
+    dispose() {
+      if (frame !== null) {
+        cancelAnimationFrame(frame)
+        frame = null
+      }
+      task = null
+    },
+  }
+}
@@ -137,3 +137,16 @@ export const IconSaveOutline16 = ({ size = 16, className }: IconProps) => (
    <path d="M5.4 14.5v-4.2h5.2v4.2" stroke="currentColor" strokeWidth="1.5" strokeLinejoin="round" />
  </svg>
 )
+
+/**
+ * Visual Studio Code brand mark for the file-tree "open with" menu. The
+ * path is the Simple Icons `visualstudiocode` glyph (CC0 1.0,
+ * simple-icons@11.0.0 — later releases dropped it over Microsoft's brand
+ * policy, so it is inlined here rather than pulled from react-icons),
+ * rendered monochrome via currentColor to follow the active skin.
+ */
+export const IconVscode16 = ({ size = 16, className }: IconProps) => (
+  <svg width={size} height={size} className={className} viewBox="0 0 24 24" fill="currentColor" xmlns="http://www.w3.org/2000/svg">
+    <path d="M23.15 2.587L18.21.21a1.494 1.494 0 0 0-1.705.29l-9.46 8.63-4.12-3.128a.999.999 0 0 0-1.276.057L.327 7.261A1 1 0 0 0 .326 8.74L3.899 12 .326 15.26a1 1 0 0 0 .001 1.479L1.65 17.94a.999.999 0 0 0 1.276.057l4.12-3.128 9.46 8.63a1.492 1.492 0 0 0 1.704.29l4.942-2.377A1.5 1.5 0 0 0 24 20.06V3.939a1.5 1.5 0 0 0-.85-1.352zm-5.146 14.861L10.826 12l7.178-5.448v10.896z" />
+  </svg>
+)
@@ -30,6 +30,26 @@ export const zh = {
  editorEmptyHint: '从右侧文件树或上方路径输入框选择文件开始预览',
  openFileNewTab: '在新 Tab 中打开',
  openFileSide: '在侧边打开',
+  openWithMenu: '在应用中打开',
+  openWithSshSuffix: ' (SSH)',
+  pinOpenWith: '固定到菜单',
+  unpinOpenWith: '取消固定',
+  openWithExplorer: '资源管理器',
+  openWithVscode: 'VS Code',
+  openWithCursor: 'Cursor',
+  openWithZed: 'Zed',
+  openWithSettingsSshTitle: 'SSH 远端主机',
+  openWithSettingsSshDesc: '留空为本地工作区；填入 user@host 或 SSH 别名后，VSCode 系打开方式将改用 vscode-remote/ssh-remote 协议，资源管理器 / Zed / 非 VSCode 系自定义编辑器将从菜单隐藏',
+  openWithSettingsSshPlaceholder: 'user@host 或 SSH 别名',
+  openWithSettingsCustomTitle: '自定义编辑器',
+  openWithSettingsCustomDesc: '名称 + URL 模板（{path} 占位符）+ 是否 VSCode 系；SSH 模式下仅 VSCode 系可打开远端',
+  openWithSettingsAdd: '添加',
+  openWithSettingsName: '名称',
+  openWithSettingsTemplate: '如 cursor://file/{path}',
+  openWithSettingsFamily: 'VSCode 系',
+  openWithSettingsFamilyDesc: '该编辑器使用 VSCode 的 URL 协议（支持 SSH 远端打开）',
+  openWithSettingsRemove: '删除',
+  openWithSettingsInvalidHint: '名称或模板（需含 {path} 且以 scheme:// 开头）未填写的编辑器不会出现在菜单中',
  newTab: '新建标签页',
  openExplorer: '资源管理器',
  brokenSymlink: '失效的软链接',
@@ -37,6 +57,9 @@ export const zh = {
  newTerminal: '新终端',
  terminalLimit: '终端数量已达上限 (3)',
  close: '关闭',
+  closeOtherTabs: '关闭其他页签',
+  closeLeftTabs: '关闭左侧页签',
+  closeRightTabs: '关闭右侧页签',
  collapse: '折叠侧边栏',
  expand: '展开侧边栏',
  collapseBottomPanel: '折叠底部面板',
@@ -337,6 +360,26 @@ export const en: Record<keyof typeof zh, string> = {
  editorEmptyHint: 'Pick a file from the tree panel or the path input above to start previewing',
  openFileNewTab: 'Open in New Tab',
  openFileSide: 'Open to the Side',
+  openWithMenu: 'Open with',
+  openWithSshSuffix: ' (SSH)',
+  pinOpenWith: 'Pin to menu',
+  unpinOpenWith: 'Unpin',
+  openWithExplorer: 'File Manager',
+  openWithVscode: 'VS Code',
+  openWithCursor: 'Cursor',
+  openWithZed: 'Zed',
+  openWithSettingsSshTitle: 'SSH remote host',
+  openWithSettingsSshDesc: 'Empty = local workspace; with a user@host or SSH alias, VSCode-family openers switch to the vscode-remote/ssh-remote protocol and the File Manager / Zed / non-VSCode-family custom editors are hidden from the menu',
+  openWithSettingsSshPlaceholder: 'user@host or SSH alias',
+  openWithSettingsCustomTitle: 'Custom editors',
+  openWithSettingsCustomDesc: 'Name + URL template ({path} placeholder) + VSCode-family flag; in remote mode only VSCode-family editors can open a remote path',
+  openWithSettingsAdd: 'Add',
+  openWithSettingsName: 'Name',
+  openWithSettingsTemplate: 'e.g. cursor://file/{path}',
+  openWithSettingsFamily: 'VSCode-family',
+  openWithSettingsFamilyDesc: 'This editor speaks the VSCode URL dialect (supports SSH-remote opens)',
+  openWithSettingsRemove: 'Remove',
+  openWithSettingsInvalidHint: 'Editors with a missing name or a template without {path} / scheme:// are not shown in the menu',
  newTab: 'New tab',
  openExplorer: 'Explorer',
  brokenSymlink: 'Broken symlink',
@@ -344,6 +387,9 @@ export const en: Record<keyof typeof zh, string> = {
  newTerminal: 'New terminal',
  terminalLimit: 'Terminal limit reached (3)',
  close: 'Close',
+  closeOtherTabs: 'Close Other Tabs',
+  closeLeftTabs: 'Close Tabs to the Left',
+  closeRightTabs: 'Close Tabs to the Right',
  collapse: 'Collapse sidebar',
  expand: 'Expand sidebar',
  collapseBottomPanel: 'Collapse bottom panel',
@@ -0,0 +1,135 @@
+/**
+ * The editor tab's custom settings panel ("打开方式"): the file tree's
+ * "open with" configuration — the optional SSH host marking the workspace as
+ * remote, and the user-defined editors (name + URL template with `{path}` +
+ * whether they speak the VSCode URL dialect). Persisted as the editor
+ * blob's `openWith` key through the settings popup's `updatePluginSetting`.
+ *
+ * The popup renders the declarative rows (the editorExplorer picker) ABOVE
+ * this panel — SettingsBody renders the custom panel after the row list, so
+ * this component owns only its own section.
+ */
+import { useState } from 'react'
+import { IconCloseOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
+import {
+  isValidCustomEditor,
+  newCustomEditorId,
+  parseOpenWithConfig,
+  type CustomEditor,
+  type OpenWithConfig,
+} from './open-with.ts'
+import { t } from './locales.ts'
+import css from './SideCardSection.module.css'
+
+export function OpenWithSettings(props: {
+  pluginSettings: Record<string, unknown>
+  updatePluginSetting: (key: string, value: unknown) => void
+}) {
+  const { pluginSettings, updatePluginSetting } = props
+  // Local draft seeded from the persisted blob (each commit re-renders the
+  // popup with the round-tripped prefs; the local state stays authoritative
+  // while the popup is open, so typing never fights an in-flight write).
+  const [draft, setDraft] = useState<OpenWithConfig>(() => parseOpenWithConfig(pluginSettings.openWith))
+
+  const commit = (next: OpenWithConfig): void => {
+    setDraft(next)
+    updatePluginSetting('openWith', next)
+  }
+
+  const setSshHost = (sshHost: string): void => commit({ ...draft, sshHost })
+
+  const patchCustom = (id: string, patch: Partial<CustomEditor>): void => {
+    commit({
+      ...draft,
+      customEditors: draft.customEditors.map(editor => editor.id === id ? { ...editor, ...patch } : editor),
+    })
+  }
+
+  const removeCustom = (id: string): void => {
+    commit({
+      ...draft,
+      customEditors: draft.customEditors.filter(editor => editor.id !== id),
+      // A removed editor can never stay pinned (the menu prunes unknown ids
+      // anyway; this keeps the blob clean).
+      pinned: draft.pinned.filter(pinnedId => pinnedId !== `custom:${id}`),
+    })
+  }
+
+  const addCustom = (): void => {
+    commit({
+      ...draft,
+      customEditors: [...draft.customEditors, { id: newCustomEditorId(), name: '', urlTemplate: '', isVscodeFamily: false }],
+    })
+  }
+
+  const hasInvalid = draft.customEditors.some(editor => !isValidCustomEditor(editor))
+
+  return (
+    <div className={css.popupRows}>
+      <div className={css.popupRow}>
+        <span className={css.rowText}>
+          <span className={css.title}>{t('openWithSettingsSshTitle')}</span>
+          <span className={css.desc}>{t('openWithSettingsSshDesc')}</span>
+        </span>
+        <input
+          className={css.typedInput}
+          value={draft.sshHost}
+          placeholder={t('openWithSettingsSshPlaceholder')}
+          spellCheck={false}
+          onChange={(event) => { setSshHost(event.target.value) }}
+        />
+      </div>
+      <div className={css.popupRow}>
+        <span className={css.rowText}>
+          <span className={css.title}>{t('openWithSettingsCustomTitle')}</span>
+          <span className={css.desc}>{t('openWithSettingsCustomDesc')}</span>
+        </span>
+        <span className={css.control}>
+          <button type="button" className={css.done} onClick={addCustom}>
+            {t('openWithSettingsAdd')}
+          </button>
+        </span>
+      </div>
+      {draft.customEditors.map(editor => (
+        <div key={editor.id} className={css.openWithEditorRow}>
+          <input
+            className={css.openWithEditorInput}
+            value={editor.name}
+            placeholder={t('openWithSettingsName')}
+            spellCheck={false}
+            onChange={(event) => { patchCustom(editor.id, { name: event.target.value }) }}
+          />
+          <input
+            className={css.openWithEditorTemplate}
+            value={editor.urlTemplate}
+            placeholder={t('openWithSettingsTemplate')}
+            spellCheck={false}
+            onChange={(event) => { patchCustom(editor.id, { urlTemplate: event.target.value }) }}
+          />
+          <label className={css.openWithFamily} title={t('openWithSettingsFamilyDesc')}>
+            <input
+              type="checkbox"
+              checked={editor.isVscodeFamily}
+              onChange={(event) => { patchCustom(editor.id, { isVscodeFamily: event.currentTarget.checked }) }}
+            />
+            <span>{t('openWithSettingsFamily')}</span>
+          </label>
+          <button
+            type="button"
+            className={css.openWithRemove}
+            aria-label={t('openWithSettingsRemove')}
+            title={t('openWithSettingsRemove')}
+            onClick={() => { removeCustom(editor.id) }}
+          >
+            <IconCloseOutline16 size={14} />
+          </button>
+        </div>
+      ))}
+      {hasInvalid && (
+        <div className={css.openWithHint} role="note">
+          {t('openWithSettingsInvalidHint')}
+        </div>
+      )}
+    </div>
+  )
+}
@@ -0,0 +1,221 @@
+/**
+ * The file tree's "open with" vocabulary: which external editors / file
+ * managers the context menu can hand a row's path to, how the per-user
+ * configuration (custom editors, SSH host, pinned ids) is parsed out of the
+ * persisted blob, and how the external URL is built (local `file` URLs and
+ * VSCode-family SSH-remote URLs).
+ *
+ * Pure by design (no React / no `api`), so the whole surface is unit-testable
+ * without a DOM or a host route. The menu and the settings panel only consume
+ * the exported types and functions.
+ */
+import type { CopyKey } from './locales.ts'
+
+/** One user-configured editor (persisted in `pluginSettings['editor'].openWith`). */
+export interface CustomEditor {
+  id: string
+  /** Human label shown in the menu (e.g. "Windsurf"). */
+  name: string
+  /** URL template with a `{path}` placeholder (e.g. `cursor://file/{path}`). */
+  urlTemplate: string
+  /** Whether the editor speaks the VSCode URL dialect — the only editors
+   *  with an SSH-remote form (`<scheme>://vscode-remote/ssh-remote+<host>/…`). */
+  isVscodeFamily: boolean
+}
+
+/** The per-user "open with" configuration (one key of the editor blob). */
+export interface OpenWithConfig {
+  /** SSH host (user@host or an ~/.ssh/config alias); '' = local workspace. */
+  sshHost: string
+  /** User-defined editors, appended after the built-ins. */
+  customEditors: CustomEditor[]
+  /** Ids of open-with targets pinned to the menu's top level
+   *  ('explorer' | 'vscode' | 'cursor' | 'zed' | 'custom:<id>'). */
+  pinned: string[]
+}
+
+/** One menu-visible open target (built-in or custom, SSH-filtered). */
+export interface OpenWithTarget {
+  /** Stable id (`explorer` / `vscode` / `cursor` / `zed` / `custom:<id>`). */
+  id: string
+  /** Locale key of a built-in label (custom editors carry `name` instead). */
+  nameKey?: CopyKey
+  /** User-defined label (custom editors only; '' for built-ins). */
+  name: string
+  /** 'reveal' = show in the OS file manager; 'url' = open a URL. */
+  kind: 'reveal' | 'url'
+  /** URL template with `{path}`; undefined for reveal targets. */
+  urlTemplate?: string
+  /** Whether the editor talks the VSCode URL dialect. */
+  isVscodeFamily: boolean
+  /** Hidden in SSH mode (a host-local opener cannot reach a remote path). */
+  localOnly: boolean
+}
+
+/** The default open-with configuration (fresh documents). */
+export const OPEN_WITH_DEFAULTS: OpenWithConfig = {
+  sshHost: '',
+  customEditors: [],
+  pinned: [],
+}
+
+/** The built-in open targets, in menu order. */
+export const OPEN_WITH_BUILTINS: readonly OpenWithTarget[] = [
+  {
+    id: 'explorer',
+    nameKey: 'openWithExplorer',
+    name: '',
+    kind: 'reveal',
+    isVscodeFamily: false,
+    localOnly: true,
+  },
+  {
+    id: 'vscode',
+    nameKey: 'openWithVscode',
+    name: '',
+    kind: 'url',
+    urlTemplate: 'vscode://file/{path}',
+    isVscodeFamily: true,
+    localOnly: false,
+  },
+  {
+    id: 'cursor',
+    nameKey: 'openWithCursor',
+    name: '',
+    kind: 'url',
+    urlTemplate: 'cursor://file/{path}',
+    isVscodeFamily: true,
+    localOnly: false,
+  },
+  {
+    id: 'zed',
+    nameKey: 'openWithZed',
+    name: '',
+    kind: 'url',
+    urlTemplate: 'zed://file/{path}',
+    isVscodeFamily: false,
+    localOnly: true,
+  },
+]
+
+/** Whether a persisted value makes a structurally valid custom-editor row.
+ *  Name/template may be empty — the settings panel edits rows in place and
+ *  an in-progress row must survive the round-trip; the MENU hides rows that
+ *  fail the stricter {@link isValidCustomEditor} check. */
+function isCustomEditor(value: unknown): value is CustomEditor {
+  if (value === null || typeof value !== 'object' || Array.isArray(value)) return false
+  const record = value as Record<string, unknown>
+  return typeof record.id === 'string' && record.id !== ''
+    && typeof record.name === 'string'
+    && typeof record.urlTemplate === 'string'
+    && typeof record.isVscodeFamily === 'boolean'
+}
+
+/**
+ * Parse the persisted `openWith` blob (tolerant): malformed fields fall back
+ * to the defaults, malformed custom-editor rows are dropped, and pinned ids
+ * are kept verbatim (unknown ids are pruned when the targets are resolved —
+ * the menu is the only consumer of the resolved list).
+ */
+export function parseOpenWithConfig(raw: unknown): OpenWithConfig {
+  if (raw === null || typeof raw !== 'object' || Array.isArray(raw)) return { ...OPEN_WITH_DEFAULTS }
+  const record = raw as Record<string, unknown>
+  const sshHost = typeof record.sshHost === 'string' ? record.sshHost : ''
+  const customEditors = Array.isArray(record.customEditors)
+    ? record.customEditors.filter(isCustomEditor)
+    : []
+  const pinned = Array.isArray(record.pinned)
+    ? record.pinned.filter((id): id is string => typeof id === 'string' && id !== '')
+    : []
+  return { sshHost, customEditors, pinned }
+}
+
+/** Whether a custom editor id belongs to this config (id prefix match). */
+function customIdOf(id: string): string {
+  return `custom:${id}`
+}
+
+/**
+ * The menu-visible open targets, in order (built-ins then custom editors).
+ * In SSH mode the local-only targets (the OS file manager, Zed, custom
+ * editors without the VSCode dialect) are dropped — they cannot reach a
+ * remote path. Unknown pinned ids are pruned here too.
+ */
+export function resolveOpenWithTargets(config: OpenWithConfig): OpenWithTarget[] {
+  const ssh = config.sshHost.trim() !== ''
+  const targets: OpenWithTarget[] = [
+    ...OPEN_WITH_BUILTINS,
+    ...config.customEditors
+      .filter(isValidCustomEditor)
+      .map((editor): OpenWithTarget => ({
+        id: customIdOf(editor.id),
+        name: editor.name,
+        kind: 'url',
+        urlTemplate: editor.urlTemplate,
+        isVscodeFamily: editor.isVscodeFamily,
+        localOnly: !editor.isVscodeFamily,
+      })),
+  ]
+  return targets.filter(target => !(ssh && target.localOnly))
+}
+
+/** The SSH hint appended to a target's label in remote mode. */
+export function openWithSshActive(config: OpenWithConfig): boolean {
+  return config.sshHost.trim() !== ''
+}
+
+/**
+ * The URL to open for one resolved target, or undefined when the target has
+ * no URL form (reveal) or the template is malformed. The path is inserted
+ * RAW into the template (browsers percent-encode as needed; VSCode-family
+ * URL parsers consume the absolute path with its leading slash, e.g.
+ * `vscode://file//home/u/f.ts` or `vscode://file/C:/Users/u/f.ts`).
+ */
+export function openWithUrl(target: OpenWithTarget, path: string, config: OpenWithConfig): string | undefined {
+  if (target.kind !== 'url' || target.urlTemplate === undefined) return undefined
+  const normalized = normalizeUrlPath(path)
+  const ssh = openWithSshActive(config)
+  if (ssh && target.isVscodeFamily) {
+    const scheme = schemeOf(target.urlTemplate)
+    if (scheme === undefined) return undefined
+    // `ssh-remote+<host>` owns NO slash of its own: the path keeps its
+    // leading slash, so `/home/u/f.ts` lands as `…+host/home/u/f.ts`.
+    return `${scheme}://vscode-remote/ssh-remote+${config.sshHost.trim()}${normalized}`
+  }
+  if (!target.urlTemplate.includes('{path}') || !hasUrlScheme(target.urlTemplate)) return undefined
+  return target.urlTemplate.replace('{path}', normalized)
+}
+
+/** Whether a template starts with a `scheme://` prefix (the only shape the
+ *  host's external opener accepts and the settings panel suggests). */
+function hasUrlScheme(template: string): boolean {
+  return /^[a-z][a-z0-9+.-]*:\/\//i.test(template)
+}
+
+/** The scheme of a URL template (the part before the first ':'), or undefined. */
+function schemeOf(template: string): string | undefined {
+  const at = template.indexOf(':')
+  if (at <= 0) return undefined
+  const scheme = template.slice(0, at)
+  return /^[a-z][a-z0-9+.-]*$/i.test(scheme) ? scheme : undefined
+}
+
+/** Normalize a filesystem path for embedding in a URL (backslashes → '/'). */
+export function normalizeUrlPath(path: string): string {
+  return path.replace(/\\/g, '/')
+}
+
+/** A fresh custom-editor id (uuid when available, time-based fallback). */
+export function newCustomEditorId(): string {
+  if (typeof crypto !== 'undefined' && typeof crypto.randomUUID === 'function') {
+    return crypto.randomUUID()
+  }
+  return `${Date.now().toString(36)}${Math.random().toString(36).slice(2)}`
+}
+
+/** Validate one custom-editor row before the settings panel accepts it. */
+export function isValidCustomEditor(row: { name: string; urlTemplate: string }): boolean {
+  return row.name.trim() !== ''
+    && row.urlTemplate.includes('{path}')
+    && /^[a-z][a-z0-9+.-]*:\/\//i.test(row.urlTemplate.trim())
+}
@@ -0,0 +1,43 @@
+/**
+ * Pending-writes queue for the file tree's open-with config: pin toggles and
+ * (outside the settings popup) config edits land in the sidebar prefs as
+ * `pluginSettings['editor']`. Writes are serialized through one promise chain
+ * so a quick burst of pin clicks can never read a stale pluginSettings map
+ * and drop an earlier toggle; each write pushes the whole open map patch
+ * through the revision-free settings route and adopts the returned document.
+ *
+ * (The settings popup has its own serialized commit — SideCardSection's —
+ * so its rows and this helper rarely race; the shared route's last-write-wins
+ * semantics cover the uncommon overlap.)
+ */
+import { api } from './api.ts'
+import { parsePrefs } from './prefs.ts'
+import type { SidebarStore } from './state.ts'
+
+let queue: Promise<void> = Promise.resolve()
+
+/**
+ * Merge one plugin-owned settings blob of one descriptor and persist it.
+ * @param store - the sidebar store (its prefs are replaced by the write result).
+ * @param descriptorId - the descriptor whose blob is patched ('editor' here).
+ * @param updater - pure patch function; receives a shallow copy of the blob.
+ */
+export function updatePluginSettings(
+  store: SidebarStore,
+  descriptorId: string,
+  updater: (blob: Record<string, unknown>) => Record<string, unknown>,
+): void {
+  queue = queue.then(async () => {
+    const prefs = store.getPrefs()
+    const blob = prefs.pluginSettings[descriptorId] ?? {}
+    const next = updater({ ...blob })
+    const view = await api.settingsUpdate({
+      pluginSettings: { ...prefs.pluginSettings, [descriptorId]: next },
+    })
+    store.setPrefs(parsePrefs(view.value))
+  }).catch((error: unknown) => {
+    // The pin stays visually unchanged (no optimistic flip) and the menu
+    // keeps working — the write failure is logged, not surfaced.
+    console.error('open-with settings write failed', error)
+  })
+}
@@ -470,7 +470,7 @@ export function matchUrlTarget(tabs: readonly TabDescriptor[], url: URL): TabDes
 * The plugin version this service instance reports. Keep in lockstep with
 * `package.json`'s version — `tests/service.spec.ts` asserts the pair.
 */
-export const SIDEBAR_SERVICE_VERSION = '0.15.1'
+export const SIDEBAR_SERVICE_VERSION = '0.15.2'

 /**
 * Monotonic capability list consumers use to gate new API usage (features
@@ -2132,10 +2132,34 @@ body[data-dsh-sidebar-dragging] .bottomPanel {

 /* One changed file's section: path header, hunk headers, aligned lines. */
 .gitDiffFile {
+  width: 100%;
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 8px 2px 2px;
+  border: 0;
+  background: transparent;
+  color: inherit;
+  text-align: left;
+  cursor: pointer;
+}
+
+.gitDiffFile:disabled {
+  cursor: default;
+}
+
+.gitDiffFile:hover:not(:disabled) {
+  background: var(--dsw-alias-interactive-bg-hover);
+}
+
+.gitDiffFileChevron {
+  flex: none;
+  color: var(--dsw-alias-label-tertiary);
+  transform: rotate(0deg);
+}
+
+.gitDiffFileChevronExpanded {
+  transform: rotate(90deg);
 }

 .gitDiffFilePath {
@@ -2441,6 +2465,7 @@ body[data-dsh-sidebar-dragging] .bottomPanel {
 .gitCommitButton:focus-visible,
 .gitLogRow:focus-visible,
 .gitLogMore:focus-visible,
+.gitDiffFile:focus-visible,
 .gitDiffExpand:focus-visible,
 .terminalRetry:focus-visible,
 .editorModeButton:focus-visible,
@@ -2496,3 +2521,54 @@ body[data-dsh-sidebar-dragging] .bottomPanel {
    max-width: 128px;
  }
 }
+
+/* The file tree "open with" menu rows: the label area is a BLOCK-level flex
+   row that fills the primitives `.itemLabel` span (which is itself `flex: 1`
+   inside the row), so the trailing control — the pushpin on submenu rows,
+   the chevron on the submenu parent — docks at the row's far right, exactly
+   like the trailing check on selected rows of every other menu. */
+.openWithLabel {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  width: 100%;
+  min-width: 0;
+}
+
+.openWithName {
+  flex: 1 1 auto;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+/* The trailing "expands into a submenu" chevron on the open-with parent row
+   (the primitives Menu renders no arrow for submenu parents). */
+.openWithChevron {
+  flex: none;
+  color: var(--dsw-alias-label-tertiary);
+}
+
+/* The pushpin toggle on an "open with" submenu row: brand ink once the
+   target is pinned to the menu's top level. */
+.openWithPin {
+  flex: none;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 20px;
+  height: 20px;
+  border-radius: 6px;
+  color: var(--dsw-alias-label-tertiary);
+  cursor: pointer;
+}
+
+.openWithPin:hover {
+  background: var(--dsw-alias-interactive-bg-hover);
+  color: var(--dsw-alias-label-primary);
+}
+
+.openWithPinActive {
+  color: var(--dsw-alias-state-business-primary);
+}
@@ -15,6 +15,7 @@ import clsx from 'clsx'
 import type { SidebarState, SidebarTab, SplitNode } from './state.ts'
 import type { DropZone } from './state.ts'
 import { TabBar, type NewTabOption, parseDrag, type TabDragPayload } from './TabBar.tsx'
+import { createFrameBatcher } from './frame-batcher.ts'
 import css from './sidebar.module.css'

 /** Actions the workbench needs (bound to the store by the sidebar shell). */
@@ -34,7 +35,18 @@ export interface WorkbenchActions {
 * Deltas are incremental — each move reports the displacement since the
 * previous move — because the store adds every reported delta to the pane
 * sizes; a cumulative (since-pointer-down) delta would be re-added on each
- * move and the divider would run away from the cursor. */
+ * move and the divider would run away from the cursor.
+ *
+ * The moves are BATCHED per frame (createFrameBatcher): a pointer stream
+ * fires faster than the display refresh, and applying each move is a store
+ * reduce that re-renders both workbenches (terminals, editors, trees) per
+ * event — the visible drag lag on slower CPUs (#315). The batch accumulates
+ * the incremental deltas in a ref and applies the summed fraction at most
+ * once per frame; the sum equals what the per-event application would have
+ * produced (the reducer clamps each application, and at a settled position
+ * a clamped sum is clamped to the same boundary), so the result is
+ * indistinguishable at rest and at most one frame behind the cursor.
+ */
 function Divider(props: { dir: 'row' | 'col'; onResize: (deltaFrac: number) => void }) {
  const { dir, onResize } = props
  // `last` is the previous pointer position while dragging; `size` is the
@@ -42,6 +54,9 @@ function Divider(props: { dir: 'row' | 'col'; onResize: (deltaFrac: number) => v
  // normalize the px delta into a fraction.
  const last = useRef({ x: 0, y: 0, size: 0 })
  const [dragging, setDragging] = useState(false)
+  const pendingDelta = useRef(0)
+  const batcher = useRef(createFrameBatcher()).current
+  useEffect(() => () => batcher.dispose(), [batcher])

  return (
    <div
@@ -60,12 +75,20 @@ function Divider(props: { dir: 'row' | 'col'; onResize: (deltaFrac: number) => v
      onPointerMove={(event) => {
        if (!event.currentTarget.hasPointerCapture(event.pointerId)) return
        const delta = dir === 'row' ? event.clientX - last.current.x : event.clientY - last.current.y
-        onResize(delta / Math.max(1, last.current.size))
+        pendingDelta.current += delta
+        batcher.schedule(() => {
+          const accumulated = pendingDelta.current
+          pendingDelta.current = 0
+          if (accumulated !== 0) onResize(accumulated / Math.max(1, last.current.size))
+        })
        last.current.x = event.clientX
        last.current.y = event.clientY
      }}
      onPointerUp={(event) => {
        if (!event.currentTarget.hasPointerCapture(event.pointerId)) return
+        // Flush any pending baked delta so the final pointer position lands
+        // (the release event is not a move; dropping it would lose the tail).
+        batcher.flushNow()
        event.currentTarget.releasePointerCapture(event.pointerId)
        setDragging(false)
      }}
@@ -825,8 +825,9 @@ export function sanitizeState(parsed: unknown): SidebarState | undefined {
  // bottom tree.
  const seen = new Set<string>()
  const reid = new Map<string, string>()
-  const splits = sanitizeNode(record.splits, seen, reid)
-  if (splits === undefined) return undefined
+  const restoredSplits = sanitizeNode(record.splits, seen, reid)
+  if (restoredSplits === undefined) return undefined
+  const splits = pruneEmptyPanes(restoredSplits)
  // Bottom-panel fields arrived in a later build: a missing or malformed
  // value on an OLDER persisted state defaults (closed / default height /
  // empty pane) so existing layouts keep loading, like nextBrowser.
@@ -840,15 +841,23 @@ export function sanitizeState(parsed: unknown): SidebarState | undefined {
    ? record.bottomHeight
    : BOTTOM_DEFAULT
  const bottomHeight = Math.min(bottomCap, Math.max(BOTTOM_MIN, Math.round(rawHeight)))
-  const bottomSplits = sanitizeNode(record.bottomSplits, seen, reid)
-    ?? { kind: 'leaf' as const, id: uid('pane'), tabs: [], active: null }
+  const bottomSplits = pruneEmptyPanes(sanitizeNode(record.bottomSplits, seen, reid)
+    ?? { kind: 'leaf' as const, id: uid('pane'), tabs: [], active: null })
+  const requestedActivePane = typeof record.activePane === 'string'
+    ? (reid.get(record.activePane) ?? record.activePane)
+    : null
+  const activePane = requestedActivePane === null
+    ? null
+    : treeHasId(splits, requestedActivePane) || treeHasId(bottomSplits, requestedActivePane)
+      ? requestedActivePane
+      : firstLeaf(splits).id
  const maxWidth = typeof window !== 'undefined' ? window.innerWidth : Infinity
  return {
    panelOpen: record.panelOpen,
    width: Math.max(PANEL_MIN, Math.min(record.width, maxWidth)),
    // A stale duplicate pane id may have been re-ided; follow the rename so
    // new tabs still land in the pane the user was using.
-    activePane: typeof record.activePane === 'string' ? (reid.get(record.activePane) ?? record.activePane) : null,
+    activePane,
    nextTerminal: record.nextTerminal,
    nextBrowser,
    expanded: record.expanded as string[],
@@ -863,6 +872,16 @@ export function sanitizeState(parsed: unknown): SidebarState | undefined {
  }
 }

+/** Collapse persisted split panes left empty after ephemeral diff tabs are dropped. */
+function pruneEmptyPanes(node: SplitNode): SplitNode {
+  const leaves = allLeaves(node)
+  if (!leaves.some(leaf => leaf.tabs.length > 0)) return node
+  return leaves.reduce(
+    (tree, leaf) => leaf.tabs.length === 0 ? removeLeafAt(tree, leaf.id) : tree,
+    node,
+  )
+}
+
 /**
 * One tree node id, deduplicated against the ids already seen in this
 * state. Duplicates are exactly the pre-seeding counter-reset corruption
@@ -0,0 +1,46 @@
+/**
+ * The memo comparator for one tab's content cell (TabContent in Sidebar.tsx).
+ *
+ * Kept as a pure module so the "what re-renders a tab cell" contract is unit
+ * testable: geometry/store re-renders of the Sidebar shell must NOT reconcile
+ * every mounted tab (xterm/CodeMirror/FileTree subtrees — issue #315), while
+ * locale switches (localeRevision), tab-registry updates (tabsVersion), and
+ * a tab MOVING BETWEEN PANES (paneId — onOpenDiff closes over the pane id,
+ * and moveTab reuses the SAME tab object, so only the pane id identifies the
+ * move) must re-render the cell.
+ */
+import type { SidebarTab } from './state.ts'
+
+/** The fields whose change invalidates a tab cell's memo. Anything a cell's
+ *  render (or its callbacks) depends on must be listed here. */
+export interface TabContentMemoKey {
+  tab: SidebarTab
+  /** The pane this tab currently lives in. onOpenDiff closes over it, and
+   *  moveTab reuses the same tab object when the tab moves panes — without
+   *  comparing paneId the cell would keep the source pane's callback. */
+  paneId: string
+  sessionId: string
+  cwd: string | undefined
+  visible: boolean
+  expanded: string[]
+  localeRevision: string
+  tabsVersion: number
+}
+
+/** True when the cell may skip a re-render (all render-affecting fields
+ *  unchanged). Callback/context identities are deliberately ignored: their
+ *  captured dependencies are stable or covered by the compared fields
+ *  (onReferenceFile → sessionId/cwd, onSubagentJump/onToggleDir → stable
+ *  refs/closures, onOpenDiff → paneId). */
+export function tabContentCompare(prev: TabContentMemoKey, next: TabContentMemoKey): boolean {
+  return (
+    prev.tab === next.tab &&
+    prev.paneId === next.paneId &&
+    prev.sessionId === next.sessionId &&
+    prev.cwd === next.cwd &&
+    prev.visible === next.visible &&
+    prev.expanded === next.expanded &&
+    prev.localeRevision === next.localeRevision &&
+    prev.tabsVersion === next.tabsVersion
+  )
+}
@@ -96,6 +96,7 @@ function runGit(cwd: string, args: string[], timeoutMs = 30_000): Promise<string
  return new Promise<string>((resolvePromise, reject) => {
    const child = spawn('git', full, {
      stdio: ['ignore', 'pipe', 'pipe'],
+      windowsHide: true,
      env: { ...process.env, GIT_OPTIONAL_LOCKS: '0' },
    })
    let stdout = ''
@@ -143,13 +144,20 @@ export async function currentBranch(cwd: string): Promise<string> {
  return out.trim()
 }

-/** Working-tree status (untracked included). */
+/**
+ * Working-tree status (untracked included). `--untracked-files=all` lists
+ * the CONTENTS of new directories as individual entries (`?? newdir/a.ts`
+ * rather than a collapsed `?? newdir/`), so every row in the source-control
+ * panel is a real file whose diff tab can load. With `=normal`, git folds a
+ * new folder into one trailing-slash entry that has no diff output and
+ * cannot be read as a file.
+ */
 export async function status(cwd: string): Promise<GitStatusResult> {
  const repo = await isGitRepo(cwd)
  if (!repo) return { isRepo: false, entries: [] }
  const [branch, raw] = await Promise.all([
    currentBranch(cwd).catch(() => 'HEAD'),
-    runGit(cwd, ['status', '--porcelain=v1', '-z', '--untracked-files=normal']),
+    runGit(cwd, ['status', '--porcelain=v1', '-z', '--untracked-files=all']),
  ])
  return { isRepo: true, branch, entries: parsePorcelainZ(raw) }
 }
@@ -35,6 +35,7 @@ import { decodeHtmlUrl } from './html-route.ts'
 import { extractFrameAncestors } from './browser-probe.ts'
 import { isTrustedApiRequest, isLoopbackHostname } from './trust-fence.ts'
 import { registerBundleRoute } from './bundle-route.ts'
+import { launchExternal } from './open-external.ts'
 import * as git from './git.ts'
 import { SettingsConflictError, settingsNamespace, type SettingsNamespace } from '@deepseek-ai/dsh-settings'
 import { defaultShell, ensureSpawnHelper, PtyManager, shellDisplayName } from './pty-manager.ts'
@@ -479,6 +480,19 @@ function buildApi(
        clearTimeout(timer)
      }
    },
+    // External open for the file tree's "open with" menu: reveal a path in
+    // the OS file manager, or hand a custom-scheme URL (vscode://,
+    // cursor://, zed://, custom editors) to its registered handler. The
+    // client is a browser renderer where raw scheme navigation is
+    // unreliable, so the launch always goes through the host — the same
+    // fence as every other route, argv-only (no shell interpolation).
+    'open.external': (payload) => {
+      const record = payload as { action?: unknown } | null
+      const action = record?.action
+      if (action === 'reveal') return launchExternal('reveal', requireString(payload, 'path'))
+      if (action === 'url') return launchExternal('url', requireString(payload, 'url'))
+      throw new SidebarError('bad-request', 'action must be "reveal" or "url"')
+    },
    // Side Chat: create a side-thread child seeded with the parent's full
    // log up to now, deliver follow-ups (cold-resuming when the thread's
    // agent is gone), abort a running thread, and release a thread's agent.
@@ -0,0 +1,90 @@
+/**
+ * External open actions for the file tree's "open with" menu: hand a path to
+ * the OS file manager (reveal/select) or launch a URL scheme's registered
+ * handler (vscode://, cursor://, zed://, custom schemes).
+ *
+ * The client runs in a browser / DSH Desktop renderer where a raw `vscode://`
+ * navigation is unreliable, so both actions fan out through this host route
+ * and spawn the platform opener with an argv array (no shell interpolation).
+ * The command builders are pure — the platform is injectable — so every
+ * per-platform branch is unit-testable without spawning anything.
+ */
+import { spawn } from 'node:child_process'
+import { parentOf, requireAbsolute } from './fs-tree.ts'
+import { SidebarError } from './wire.ts'
+
+/** The two external open actions the route accepts. */
+export type OpenExternalAction = 'reveal' | 'url'
+
+/** One platform opener invocation (argv array — never a shell string). */
+export interface ExternalCommand {
+  command: string
+  args: string[]
+}
+
+/** Reveal/select a path in the OS file manager. On Linux there is no common
+ *  select protocol — the containing directory is opened instead (KISS). */
+export function revealCommand(path: string, platform: NodeJS.Platform = process.platform): ExternalCommand {
+  switch (platform) {
+    case 'darwin':
+      return { command: 'open', args: ['-R', path] }
+    // `explorer /select,<path>` — the classic "show in folder" incantation.
+    // Passed as separate argv entries (no shell); verify on Windows, with
+    // `cmd /c start "" explorer.exe "/select,<path>"` as the fallback.
+    case 'win32':
+      return { command: 'explorer.exe', args: ['/select,', path] }
+    default: {
+      const parent = parentOf(path)
+      return { command: 'xdg-open', args: [parent ?? path] }
+    }
+  }
+}
+
+/** Hand a custom-scheme URL to the OS protocol handler. */
+export function urlCommand(url: string, platform: NodeJS.Platform = process.platform): ExternalCommand {
+  switch (platform) {
+    case 'darwin':
+      return { command: 'open', args: [url] }
+    // url.dll,FileProtocolHandler launches the registered protocol handler;
+    // `cmd /c start "" <url>` is the fallback if rundll32 misbehaves.
+    case 'win32':
+      return { command: 'rundll32.exe', args: ['url.dll,FileProtocolHandler', url] }
+    default:
+      return { command: 'xdg-open', args: [url] }
+  }
+}
+
+/** Validate a URL-scheme open target: a parseable custom-scheme URL (never
+ *  http/https — those would only dump the URL into a browser tab). */
+export function validateExternalUrl(raw: string): string {
+  if (!/^[a-z][a-z0-9+.-]*:\/\//i.test(raw)) {
+    throw new SidebarError('bad-request', 'url must be a custom-scheme URL')
+  }
+  let url: URL
+  try {
+    url = new URL(raw)
+  } catch {
+    throw new SidebarError('bad-request', 'invalid url')
+  }
+  if (url.protocol === 'http:' || url.protocol === 'https:') {
+    throw new SidebarError('bad-request', 'only custom-scheme urls can be opened externally')
+  }
+  return raw
+}
+
+/**
+ * Launch one external open action and return immediately (detached, no
+ * stdio). Spawn failures are reported through the child's 'error' event —
+ * by then the route already returned, so the event is swallowed (the OS
+ * dialog about a missing handler is the user-visible outcome either way).
+ */
+export function launchExternal(action: OpenExternalAction, value: string): { started: true } {
+  const platform = process.platform
+  const spec = action === 'reveal'
+    ? revealCommand(requireAbsolute(value), platform)
+    : urlCommand(validateExternalUrl(value), platform)
+  const child = spawn(spec.command, spec.args, { detached: true, stdio: 'ignore' })
+  child.on('error', () => { /* opener missing/denied: handled by the OS */ })
+  child.unref()
+  return { started: true }
+}
@@ -94,6 +94,9 @@ describe('built-in tab registrations', () => {
    const options = toggles[0]?.options ?? []
    expect(options.map(o => o.value)).toEqual([true, false])
    expect(options.every(o => o.icon !== undefined && o.title !== undefined)).toBe(true)
+    // The open-with configuration (SSH host + custom editors) is the custom
+    // panel rendered below the declarative rows.
+    expect(service.getTab('editor')?.settings?.render).toBeDefined()
  })

  it('the terminal tab declares the model terminal-tools, auto-terminal, shell and custom-font settings', () => {
@@ -0,0 +1,59 @@
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it } from 'vitest'
+import { createElement } from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { act } from 'react-dom/test-utils'
+import { DiffView } from '../src/client/DiffView.tsx'
+
+;(globalThis as Record<string, unknown>).IS_REACT_ACT_ENVIRONMENT = true
+
+const diff = [
+  'diff --git a/src/a.ts b/src/a.ts',
+  '--- a/src/a.ts',
+  '+++ b/src/a.ts',
+  '@@ -1 +1 @@',
+  '-old-a',
+  '+new-a',
+  'diff --git a/tests/b.spec.ts b/tests/b.spec.ts',
+  '--- a/tests/b.spec.ts',
+  '+++ b/tests/b.spec.ts',
+  '@@ -1 +1 @@',
+  '-old-b',
+  '+new-b',
+  'diff --git a/README.md b/README.md',
+  '--- a/README.md',
+  '+++ b/README.md',
+  '@@ -1 +1 @@',
+  '-old-doc',
+  '+new-doc',
+].join('\n')
+
+afterEach(() => { document.body.innerHTML = '' })
+
+describe('DiffView file folding', () => {
+  it('expands source by default while tests and docs stay collapsed', () => {
+    const container = document.createElement('div')
+    document.body.append(container)
+    const root: Root = createRoot(container)
+    try {
+      act(() => { root.render(createElement(DiffView, { diff })) })
+      const headers = [...container.querySelectorAll<HTMLButtonElement>('button[aria-expanded]')]
+      expect(headers).toHaveLength(3)
+      expect(headers.map(header => header.getAttribute('aria-expanded'))).toEqual(['true', 'false', 'false'])
+      expect(container.textContent).toContain('new-a')
+      expect(container.textContent).not.toContain('new-b')
+      expect(container.textContent).not.toContain('new-doc')
+
+      act(() => { headers[1]!.click() })
+      expect(headers[1]!.getAttribute('aria-expanded')).toBe('true')
+      expect(container.textContent).toContain('new-b')
+
+      act(() => { headers[0]!.click() })
+      expect(headers[0]!.getAttribute('aria-expanded')).toBe('false')
+      expect(container.textContent).not.toContain('new-a')
+    } finally {
+      act(() => { root.unmount() })
+      container.remove()
+    }
+  })
+})
@@ -0,0 +1,199 @@
+/**
+ * Toggle-layout lane (issue #315): while the right panel slides open/closed
+ * with its 300ms layout push, the BOTTOM panel must keep tracking the center
+ * column's horizontal edges frame by frame.
+ *
+ * The shell changed the bottom panel's geometry source from React state
+ * (setCenterRect per ResizeObserver frame → full Sidebar re-render at
+ * animation cadence) to a ref + direct inline writes, so the panel still
+ * follows the animated center column with zero React work. This lane samples
+ * the transition and asserts the bottom panel's edges stay glued to the
+ * center column (left/right within a rounding + one-frame tolerance) — the
+ * visual-equivalence proof for that change.
+ *
+ * The server is booted by scripts/e2e-mount.sh; this spec only loads the
+ * page (own workspace, like drag-layout.e2e.ts).
+ */
+import { mkdirSync, writeFileSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { test, expect, request, type APIRequestContext } from '@playwright/test'
+
+const BASE_URL = process.env.DSH_E2E_URL
+if (!BASE_URL) {
+  throw new Error('DSH_E2E_URL is not set — boot a DSH web instance with the plugin mounted and point this lane at it (see scripts/e2e-mount.sh)')
+}
+
+const WORKSPACE_PATH = process.env.DSH_E2E_TOGGLE_WORKSPACE ?? join(tmpdir(), 'dsh-e2e-toggle-workspace')
+
+let api: APIRequestContext
+
+async function seedSession(): Promise<void> {
+  mkdirSync(WORKSPACE_PATH, { recursive: true })
+  writeFileSync(join(WORKSPACE_PATH, 'seed.txt'), 'toggle lane\n')
+  const workspace = await api.post(`${BASE_URL}/api/workspace.create`, {
+    data: { type: 'client-request', rpcId: 'e2e-toggle-workspace', method: 'workspace.create', payload: { path: WORKSPACE_PATH } },
+  })
+  expect(workspace.ok(), `workspace.create: ${workspace.status()} ${await workspace.text()}`).toBe(true)
+  const workspaceBody = (await workspace.json()) as {
+    result: { ok: true; value: { workspace: { workspaceId: string } } } | { ok: false; error: unknown }
+  }
+  expect(workspaceBody.result.ok).toBe(true)
+  const workspaceId = (workspaceBody.result as { value: { workspace: { workspaceId: string } } }).value.workspace.workspaceId
+  const session = await api.post(`${BASE_URL}/api/session.create`, {
+    data: { type: 'client-request', rpcId: 'e2e-toggle-session', method: 'session.create', payload: { workspaceId } },
+  })
+  expect(session.ok(), `session.create: ${session.status()} ${await session.text()}`).toBe(true)
+}
+
+test.beforeAll(async () => {
+  api = await request.newContext({ baseURL: BASE_URL })
+  await seedSession()
+})
+
+test.afterAll(async () => {
+  await api?.dispose()
+})
+
+interface FrameSample {
+  t: number
+  centerLeft: number
+  centerRight: number
+  bottomLeft: number
+  bottomRight: number
+}
+
+test('bottom panel tracks the center column during the right-panel toggle transition (issue #315)', async ({ page }) => {
+  await page.goto(BASE_URL, { waitUntil: 'domcontentloaded' })
+  await expect(page.locator('#root > *')).not.toHaveCount(0, { timeout: 90_000 })
+  const sidebar = page.locator('[data-dsh-better-sidebar]')
+  await expect(sidebar).toBeAttached({ timeout: 90_000 })
+
+  // Dismiss onboarding (same dance as the drag lane).
+  try {
+    await expect
+      .poll(() => page.getByRole('button', { name: /^(Continue|Configure later)$/ }).count(), { timeout: 60_000 })
+      .toBeGreaterThan(0)
+  } catch {
+    console.warn('[e2e-toggle] no onboarding takeover appeared; proceeding')
+  }
+  for (let round = 0; round < 8; round++) {
+    let dismissed = false
+    for (const name of ['Continue', 'Configure later']) {
+      const button = page.getByRole('button', { name, exact: true }).first()
+      if ((await button.count()) === 0) continue
+      try {
+        await button.click({ timeout: 4_000 })
+        dismissed = true
+        await page.waitForTimeout(800)
+      } catch {
+        // Masked by a takeover stacked above; retry in the next round.
+      }
+    }
+    if (!dismissed) break
+  }
+
+  // Open the right panel (fresh sessions start collapsed).
+  const expandButton = sidebar.getByRole('button', { name: 'Expand sidebar' })
+  await expect(expandButton).toHaveCount(1)
+  await expandButton.click()
+  await expect
+    .poll(async () => {
+      const value = await page.evaluate(() => document.documentElement.style.getPropertyValue('--dsh-sidebar-width'))
+      return value !== '' && value !== '0px'
+    }, { timeout: 90_000 })
+    .toBe(true)
+
+  // Open the bottom panel too: the twin panels make the toggle exercise the
+  // full geometry chain (bottom panel edges follow the animated push).
+  const expandBottom = sidebar.getByRole('button', { name: 'Expand bottom panel' })
+  await expect(expandBottom).toHaveCount(1)
+  await expandBottom.click()
+  // Wait until the bottom panel is REALLY tracking the center column (not
+  // the hidden {0,0} fallback): the panel's box exists even while hidden, so
+  // wait for the computed visibility + a matched right edge before sampling.
+  await expect
+    .poll(async () => page.evaluate(() => {
+      const col = document.querySelector('#root [data-slot="conversation"]')?.parentElement
+      const bottom = document.querySelector('[data-dsh-bottom-panel]')
+      if (col === null || col === undefined || bottom === null) return false
+      const cr = col.getBoundingClientRect()
+      const br = bottom.getBoundingClientRect()
+      const visible = getComputedStyle(bottom).visibility !== 'hidden'
+      return cr.width > 100 && visible && Math.abs(br.right - cr.right) <= 3
+    }), { timeout: 30_000 })
+    .toBe(true)
+  await page.waitForTimeout(500) // let both open transitions settle
+
+  // Per-frame sampler: center column (same anchor as layout.css) vs the
+  // bottom panel's visible edges. The loop re-resolves
+  // window.__toggleSamples every frame, so clearing it (sampleToggle) drops
+  // old frames without detaching the loop.
+  await page.evaluate(() => {
+    const center = document.querySelector('#root [data-slot="conversation"]')?.parentElement
+    const bottom = document.querySelector('[data-dsh-bottom-panel]')
+    ;(window as unknown as { __toggleSamples: FrameSample[] }).__toggleSamples = []
+    const loop = (): void => {
+      const c = center?.getBoundingClientRect() ?? { left: 0, right: 0 }
+      const b = bottom?.getBoundingClientRect() ?? { left: 0, right: 0 }
+      ;(window as unknown as { __toggleSamples: FrameSample[] }).__toggleSamples.push({
+        t: performance.now(), centerLeft: c.left, centerRight: c.right, bottomLeft: b.left, bottomRight: b.right,
+      })
+      requestAnimationFrame(loop)
+    }
+    requestAnimationFrame(loop)
+  })
+
+  const collapseButton = sidebar.getByRole('button', { name: 'Collapse sidebar' })
+  const expandButton2 = sidebar.getByRole('button', { name: 'Expand sidebar' })
+
+  async function sampleToggle(click: () => Promise<void>): Promise<FrameSample[]> {
+    // Clear accumulated frames so the sample window starts at the click.
+    await page.evaluate(() => {
+      ;(window as unknown as { __toggleSamples: FrameSample[] }).__toggleSamples = []
+    })
+    await click()
+    await page.waitForTimeout(800)
+    const samples = await page.evaluate(() => {
+      const data = (window as unknown as { __toggleSamples: FrameSample[] }).__toggleSamples
+      ;(window as unknown as { __toggleSamples: FrameSample[] }).__toggleSamples = []
+      return data
+    })
+    return samples
+  }
+
+  function trackMiss(samples: FrameSample[], label: string): void {
+    // The bottom panel's geometry rides the center column's ResizeObserver:
+    // RO callbacks run AFTER layout, so a write there lands in the NEXT
+    // frame's paint — the panel is exactly ONE animation frame behind the
+    // column mid-transition (measured: bottom(t) === center(t-1)).
+    // Anything more is a real desync; the settled frames must agree exactly.
+    const valid = samples.filter(s => s.centerRight - s.centerLeft > 100)
+    expect(valid.length, `${label}: sampler must have captured the transition`).toBeGreaterThan(3)
+
+    let maxOneFrame = 0
+    for (let i = 1; i < valid.length; i++) {
+      maxOneFrame = Math.max(
+        maxOneFrame,
+        Math.abs(valid[i]!.bottomLeft - valid[i - 1]!.centerLeft),
+        Math.abs(valid[i]!.bottomRight - valid[i - 1]!.centerRight),
+      )
+    }
+    const settled = valid.slice(-5)
+    const settleMiss = Math.max(
+      ...settled.map(s => Math.max(
+        Math.abs(s.bottomLeft - s.centerLeft),
+        Math.abs(s.bottomRight - s.centerRight),
+      )),
+    )
+    console.log(`[e2e-toggle] ${label}: ${valid.length} frames, max one-frame miss=${maxOneFrame.toFixed(1)}px, settle miss=${settleMiss.toFixed(1)}px`)
+    expect(maxOneFrame, `${label}: bottom panel must track the center column one frame behind (RO cadence)`).toBeLessThanOrEqual(4)
+    expect(settleMiss, `${label}: bottom panel must settle exactly on the center column`).toBeLessThanOrEqual(3)
+  }
+
+  const collapseSamples = await sampleToggle(() => collapseButton.click())
+  trackMiss(collapseSamples, 'collapse')
+
+  const expandSamples = await sampleToggle(() => expandButton2.click())
+  trackMiss(expandSamples, 'expand')
+})
@@ -219,7 +219,7 @@ describe('EditorHost (files window)', () => {
    }
  })

-  it('dragging the panel edge resizes the dock and persists meta.treeWidth on release', () => {
+  it('dragging the panel edge resizes the dock and persists meta.treeWidth on release', async () => {
    const { store, ctx, homeTab } = setup()
    store.setPrefs({ ...store.getPrefs(), editorExplorer: true })
    const { container, unmount } = mountHost(ctx, store, homeTab)
@@ -232,10 +232,15 @@ describe('EditorHost (files window)', () => {
      // Drag the left edge LEFT by 100px → the right-docked panel widens.
      // Pointer capture keeps move/up on the handle (jsdom: MouseEvent with
      // pointer* type names; setPointerCapture is absent and skipped).
+      // Moves are batched to one application per frame (#315), so flush the
+      // pending frame before asserting the width.
      act(() => {
        handle.dispatchEvent(new MouseEvent('pointerdown', { bubbles: true, clientX: 300 }))
        handle.dispatchEvent(new MouseEvent('pointermove', { bubbles: true, clientX: 200 }))
      })
+      await act(async () => {
+        await new Promise<void>(resolve => requestAnimationFrame(() => resolve()))
+      })
      expect(dock.style.width).toBe('340px')
      // Release: the drag state clears and the width persists on the tab.
      act(() => { handle.dispatchEvent(new MouseEvent('pointerup', { bubbles: true, clientX: 200 })) })
@@ -0,0 +1,202 @@
+/**
+ * FileTree "open with" context menu: a file row's right-click menu gains the
+ * pinned direct rows and the parent submenu row; the submenu lists every
+ * resolved target with a per-row pushpin, pinning never selects/closes the
+ * menu, and selecting a child invokes the caller's open handler with the
+ * row's absolute path. When the caller wires nothing, the section is absent.
+ */
+// @vitest-environment jsdom
+import { beforeAll, afterEach, describe, expect, it, vi } from 'vitest'
+import { createElement } from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { act } from 'react-dom/test-utils'
+import { FileTree } from '../src/client/FileTree.tsx'
+import type { OpenWithTarget } from '../src/client/open-with.ts'
+
+// The act() environment flag (React 18.2 reads it before flushing effects).
+;(globalThis as Record<string, unknown>).IS_REACT_ACT_ENVIRONMENT = true
+
+// vitest 4.1.11+ follows the OS locale; pin en-US so menu copy is English.
+beforeAll(() => {
+  Object.defineProperty(window.navigator, 'language', { value: 'en-US', configurable: true })
+})
+
+vi.mock('../src/client/api.ts', () => ({
+  api: {
+    fsTree: async () => ({
+      entries: [{ name: 'a.ts', path: '/tmp/a.ts', isDir: false }],
+    }),
+  },
+  downloadUrl: () => '/sidebar/file',
+}))
+
+/** The resolved target list a caller (EditorHost) would hand FileTree. */
+const targets: OpenWithTarget[] = [
+  { id: 'explorer', nameKey: 'openWithExplorer', name: '', kind: 'reveal', isVscodeFamily: false, localOnly: true },
+  { id: 'vscode', nameKey: 'openWithVscode', name: '', kind: 'url', urlTemplate: 'vscode://file/{path}', isVscodeFamily: true, localOnly: false },
+  { id: 'cursor', nameKey: 'openWithCursor', name: '', kind: 'url', urlTemplate: 'cursor://file/{path}', isVscodeFamily: true, localOnly: false },
+  { id: 'zed', nameKey: 'openWithZed', name: '', kind: 'url', urlTemplate: 'zed://file/{path}', isVscodeFamily: false, localOnly: true },
+  { id: 'custom:w', name: 'Windsurf', kind: 'url', urlTemplate: 'windsurf://file/{path}', isVscodeFamily: false, localOnly: false },
+]
+
+interface Harness {
+  container: HTMLDivElement
+  onOpenWith: ReturnType<typeof vi.fn>
+  onToggleOpenWithPin: ReturnType<typeof vi.fn>
+  unmount: () => void
+}
+
+async function mountTree(overrides: {
+  openWithTargets?: OpenWithTarget[]
+  openWithPinned?: string[]
+  openWithSsh?: boolean
+} = {}): Promise<Harness> {
+  const container = document.createElement('div')
+  document.body.append(container)
+  const root: Root = createRoot(container)
+  const onOpenWith = vi.fn()
+  const onToggleOpenWithPin = vi.fn()
+  // Property-presence semantics: an explicit `openWithTargets: undefined`
+  // must reach FileTree (the section hides) instead of falling back.
+  const has = (key: 'openWithTargets' | 'openWithPinned' | 'openWithSsh'): boolean =>
+    Object.prototype.hasOwnProperty.call(overrides, key)
+  await act(async () => {
+    root.render(createElement(FileTree, {
+      sessionId: 's1',
+      cwd: '/tmp',
+      expanded: [],
+      onToggle: () => {},
+      onOpenFile: () => {},
+      onOpenFileNewTab: () => {},
+      onOpenFileSide: () => {},
+      openWithTargets: has('openWithTargets') ? overrides.openWithTargets : targets,
+      openWithPinned: has('openWithPinned') ? overrides.openWithPinned : ['vscode'],
+      openWithSsh: has('openWithSsh') ? overrides.openWithSsh : false,
+      onOpenWith,
+      onToggleOpenWithPin,
+      onReferenceFile: () => {},
+      refreshTick: 0,
+      onUploadRequest: () => {},
+      busy: false,
+    }))
+  })
+  return {
+    container,
+    onOpenWith,
+    onToggleOpenWithPin,
+    unmount: () => { act(() => { root.unmount() }) },
+  }
+}
+
+/** The file row of the one-level tree (role="button" with the name span). */
+function fileRow(container: HTMLDivElement): HTMLElement {
+  const row = [...container.querySelectorAll<HTMLElement>('[role="button"]')]
+    .find(el => el.querySelector('[class*="explorerName"]')?.textContent === 'a.ts')
+  if (row === undefined) throw new Error('file row not found')
+  return row
+}
+
+/** Open the row's context menu at a fixed cursor position. */
+function openMenu(container: HTMLDivElement): void {
+  const event = new MouseEvent('contextmenu', { bubbles: true, cancelable: true, clientX: 20, clientY: 30 })
+  act(() => { fileRow(container).dispatchEvent(event) })
+}
+
+describe('FileTree open-with menu', () => {
+  let harness: Harness
+  afterEach(() => {
+    harness.unmount()
+    document.body.innerHTML = ''
+  })
+
+  it('renders the pinned direct row and the submenu parent for a file row', async () => {
+    harness = await mountTree()
+    openMenu(harness.container)
+    const items = [...document.querySelectorAll<HTMLElement>('[role="menuitem"]')]
+    // The pinned VS Code sits at the top level (before the submenu parent).
+    expect(items.map(item => item.textContent?.trim())).toContain('VS Code')
+    const parent = items.find(item => item.getAttribute('aria-haspopup') === 'menu')
+    expect(parent?.textContent).toContain('Open with')
+    // The submenu parent carries the trailing chevron affordance (the
+    // primitives Menu renders no arrow of its own), right-aligned inside a
+    // full-width label row — the same structure the submenu children use.
+    expect(parent?.querySelector('[class*="openWithChevron"]')).not.toBeNull()
+    expect(parent?.querySelector('[class*="openWithLabel"]')).not.toBeNull()
+  })
+
+  it('opens the submenu on click and lists every target with pin toggles', async () => {
+    harness = await mountTree()
+    openMenu(harness.container)
+    const parent = [...document.querySelectorAll<HTMLElement>('[role="menuitem"]')]
+      .find(item => item.getAttribute('aria-haspopup') === 'menu')
+    expect(parent).toBeDefined()
+    act(() => { parent!.click() })
+    // Sub child rows = menuitems inside the nested menu.
+    const children = [...document.querySelectorAll<HTMLElement>('[role="menu"] [role="menu"] [role="menuitem"]')]
+    expect(children.map(item => item.textContent?.trim())).toEqual([
+      'File Manager', 'VS Code', 'Cursor', 'Zed', 'Windsurf',
+    ])
+    expect(children.every(item => item.querySelector('[class*="openWithPin"]') !== null)).toBe(true)
+    // Pinned state is announced per row (and swaps the pushpin glyph).
+    const vscodeRow = children.find(item => item.textContent?.trim() === 'VS Code')
+    const cursorRow0 = children.find(item => item.textContent?.trim() === 'Cursor')
+    expect(vscodeRow?.querySelector('[aria-label="Unpin"]')).not.toBeNull()
+    expect(cursorRow0?.querySelector('[aria-label="Pin to menu"]')).not.toBeNull()
+  })
+
+  it('pin click toggles without selecting the row or closing the menu', async () => {
+    harness = await mountTree()
+    openMenu(harness.container)
+    const parent = [...document.querySelectorAll<HTMLElement>('[role="menuitem"]')]
+      .find(item => item.getAttribute('aria-haspopup') === 'menu')
+    act(() => { parent!.click() })
+    const cursorRow = [...document.querySelectorAll<HTMLElement>('[role="menu"] [role="menu"] [role="menuitem"]')]
+      .find(item => item.textContent?.trim() === 'Cursor')
+    const pin = cursorRow!.querySelector<HTMLElement>('[class*="openWithPin"]')
+    expect(pin).not.toBeNull()
+    act(() => { pin!.dispatchEvent(new MouseEvent('click', { bubbles: true, cancelable: true })) })
+    expect(harness.onToggleOpenWithPin).toHaveBeenCalledWith('cursor')
+    expect(harness.onOpenWith).not.toHaveBeenCalled()
+    // The menu (and the submenu) stayed open.
+    expect(document.querySelector('[role="menu"] [role="menu"]')).not.toBeNull()
+  })
+
+  it('selecting a submenu child invokes onOpenWith with the row path and closes the menu', async () => {
+    harness = await mountTree()
+    openMenu(harness.container)
+    const parent = [...document.querySelectorAll<HTMLElement>('[role="menuitem"]')]
+      .find(item => item.getAttribute('aria-haspopup') === 'menu')
+    act(() => { parent!.click() })
+    const zedRow = [...document.querySelectorAll<HTMLElement>('[role="menu"] [role="menu"] [role="menuitem"]')]
+      .find(item => item.textContent?.trim() === 'Zed')
+    act(() => { zedRow!.click() })
+    expect(harness.onOpenWith).toHaveBeenCalledWith('zed', '/tmp/a.ts')
+    // Selecting closes the row menu entirely.
+    expect(document.querySelector('[role="menu"] [role="menu"]')).toBeNull()
+    expect(document.querySelector('[role="menuitem"]')).toBeNull()
+  })
+
+  it('appends the SSH hint to VSCode-family labels in remote mode', async () => {
+    harness = await mountTree({
+      openWithSsh: true,
+      openWithTargets: targets.filter(target => !target.localOnly),
+      openWithPinned: [],
+    })
+    openMenu(harness.container)
+    const parent = [...document.querySelectorAll<HTMLElement>('[role="menuitem"]')]
+      .find(item => item.getAttribute('aria-haspopup') === 'menu')
+    act(() => { parent!.click() })
+    const children = [...document.querySelectorAll<HTMLElement>('[role="menu"] [role="menu"] [role="menuitem"]')]
+    expect(children.map(item => item.textContent?.trim())).toEqual([
+      'VS Code (SSH)', 'Cursor (SSH)', 'Windsurf (SSH)',
+    ])
+  })
+
+  it('hides the whole section when the caller wires no targets', async () => {
+    harness = await mountTree({ openWithTargets: undefined })
+    openMenu(harness.container)
+    const items = [...document.querySelectorAll<HTMLElement>('[role="menuitem"]')]
+    expect(items.some(item => item.textContent?.includes('Open with'))).toBe(false)
+    expect(items.some(item => item.getAttribute('aria-haspopup') === 'menu')).toBe(false)
+  })
+})
@@ -0,0 +1,93 @@
+/**
+ * Frame-batcher: coalesce bursty schedules into one task per animation
+ * frame, flush synchronously on release, and drop pending work on dispose.
+ * Uses a deterministic rAF stub so the coalescing contract is exact.
+ */
+// @vitest-environment jsdom
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { createFrameBatcher } from '../src/client/frame-batcher.ts'
+
+let frames: Map<number, () => void>
+let nextId: number
+
+function stepFrame(): void {
+  const callbacks = [...frames.values()]
+  frames.clear()
+  for (const callback of callbacks) callback()
+}
+
+beforeEach(() => {
+  frames = new Map()
+  nextId = 1
+  vi.stubGlobal('requestAnimationFrame', (callback: () => void) => {
+    frames.set(nextId, callback)
+    return nextId++
+  })
+  vi.stubGlobal('cancelAnimationFrame', (id: number) => {
+    frames.delete(id)
+  })
+})
+
+afterEach(() => {
+  vi.unstubAllGlobals()
+})
+
+describe('createFrameBatcher', () => {
+  it('coalesces many schedules into one task per frame (latest wins)', () => {
+    const batcher = createFrameBatcher()
+    const calls: number[] = []
+    let pending = 0
+    const apply = (value: number): void => { calls.push(value) }
+
+    // Caller pattern: compose into a ref, schedule a reader of that ref.
+    for (const value of [1, 2, 3, 4]) {
+      pending = value
+      batcher.schedule(() => apply(pending))
+    }
+    expect(calls).toEqual([])
+    stepFrame()
+    expect(calls).toEqual([4])
+    expect(frames.size).toBe(0)
+
+    // The next burst starts a fresh frame.
+    pending = 7
+    batcher.schedule(() => apply(pending))
+    stepFrame()
+    expect(calls).toEqual([4, 7])
+  })
+
+  it('flushNow runs the pending task synchronously and cancels the frame', () => {
+    const batcher = createFrameBatcher()
+    const calls: number[] = []
+    batcher.schedule(() => calls.push(1))
+    batcher.schedule(() => calls.push(2))
+    expect(frames.size).toBe(1) // still one pending frame
+
+    batcher.flushNow()
+    expect(calls).toEqual([2]) // latest task, synchronously
+    expect(frames.size).toBe(0) // frame cancelled
+
+    stepFrame() // the cancelled frame must not fire again
+    expect(calls).toEqual([2])
+
+    // flushNow when nothing is scheduled is a no-op.
+    batcher.flushNow()
+    expect(calls).toEqual([2])
+  })
+
+  it('dispose drops the pending task without running it', () => {
+    const batcher = createFrameBatcher()
+    const calls: number[] = []
+    batcher.schedule(() => calls.push(1))
+    batcher.dispose()
+    expect(frames.size).toBe(0)
+    stepFrame()
+    expect(calls).toEqual([])
+
+    // A disposed batcher accepts new schedules (React strict-mode remounts
+    // reuse the same ref-created instance semantics).
+    batcher.schedule(() => calls.push(2))
+    stepFrame()
+    expect(calls).toEqual([2])
+  })
+})
@@ -0,0 +1,41 @@
+import { EventEmitter } from 'node:events'
+import { PassThrough } from 'node:stream'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+
+const { spawnMock } = vi.hoisted(() => ({ spawnMock: vi.fn() }))
+
+vi.mock('node:child_process', () => ({ spawn: spawnMock }))
+
+import { isGitRepo } from '../src/git.ts'
+
+afterEach(() => {
+  spawnMock.mockReset()
+})
+
+describe('git subprocess spawning', () => {
+  it('hides spawned git windows', async () => {
+    spawnMock.mockImplementation(() => {
+      const child = new EventEmitter()
+      const stdout = new PassThrough()
+      const stderr = new PassThrough()
+      Object.assign(child, { stdout, stderr, kill: vi.fn() })
+
+      queueMicrotask(() => {
+        stdout.end('true\n')
+        stderr.end()
+        child.emit('close', 0)
+      })
+
+      return child
+    })
+
+    await expect(isGitRepo('C:\\repo')).resolves.toBe(true)
+
+    expect(spawnMock).toHaveBeenCalledTimes(1)
+    expect(spawnMock).toHaveBeenCalledWith(
+      'git',
+      ['-C', 'C:\\repo', '--no-pager', '-c', 'color.ui=false', 'rev-parse', '--is-inside-work-tree'],
+      expect.objectContaining({ windowsHide: true }),
+    )
+  })
+})
@@ -1,6 +1,10 @@
+import { execFileSync } from 'node:child_process'
+import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
 import { describe, expect, it } from 'vitest'
 import { parseUnifiedDiff } from '../src/client/DiffView.tsx'
-import { parseLogLines, parsePorcelainZ } from '../src/git.ts'
+import { parseLogLines, parsePorcelainZ, status } from '../src/git.ts'

 describe('git parsing', () => {
  it('parses porcelain -z entries including renames', () => {
@@ -14,6 +18,36 @@ describe('git parsing', () => {
    ])
  })

+  it('keeps untracked files inside new directories as individual rows (status --untracked-files=all)', () => {
+    // status() runs with --untracked-files=all, so a new folder must surface
+    // as one entry PER FILE (?? newdir/a.ts), never a collapsed ?? newdir/
+    // row that has no diff and cannot be read (regression: new folders showed
+    // as a single folder row whose diff tab failed with "is a directory").
+    const output = ['?? newdir/a.ts', '?? newdir/sub/b.ts', ''].join('\0')
+    expect(parsePorcelainZ(output)).toEqual([
+      { path: 'newdir/a.ts', xy: '??' },
+      { path: 'newdir/sub/b.ts', xy: '??' },
+    ])
+  })
+
+  it('keeps untracked files inside new directories as individual rows (real git)', async () => {
+    const root = mkdtempSync(join(tmpdir(), 'dsh-git-status-'))
+    try {
+      execFileSync('git', ['init', '-q'], { cwd: root })
+      execFileSync('git', ['config', 'user.email', 't@t'], { cwd: root })
+      execFileSync('git', ['config', 'user.name', 't'], { cwd: root })
+      execFileSync('git', ['commit', '-q', '--allow-empty', '-m', 'init'], { cwd: root })
+      mkdirSync(join(root, 'newdir'))
+      writeFileSync(join(root, 'newdir', 'a.ts'), 'x')
+      const result = await status(root)
+      const paths = result.entries.map(entry => entry.path)
+      expect(paths).toContain('newdir/a.ts')
+      expect(paths.some(path => path.endsWith('/'))).toBe(false)
+    } finally {
+      rmSync(root, { recursive: true, force: true })
+    }
+  })
+
  it('parses log rows with unit separators (full hash + refs)', () => {
    const rows = parseLogLines(
      'abc1234\x1fFirst subject\x1fAlice\x1f2024-01-01 10:00:00 +0800\x1fabc1234def5678abc1234def5678abc1234def5678\x1fHEAD -> main, origin/main\n'
@@ -0,0 +1,70 @@
+/**
+ * Host external-open helpers: per-platform opener commands (pure, injected
+ * platform) and the URL validation that guards the spawn route. The actual
+ * spawns are not exercised — the route runs in the DSH host process and the
+ * OS outcome is not testable here.
+ */
+import { describe, expect, it } from 'vitest'
+import { launchExternal, revealCommand, urlCommand, validateExternalUrl } from '../src/open-external.ts'
+import { SidebarError } from '../src/wire.ts'
+
+describe('revealCommand', () => {
+  it('darwin: `open -R <path>` selects the file in Finder', () => {
+    expect(revealCommand('/a/b.txt', 'darwin')).toEqual({ command: 'open', args: ['-R', '/a/b.txt'] })
+  })
+
+  it('win32: `explorer /select,<path>` selects the file', () => {
+    expect(revealCommand('C:\\a\\b.txt', 'win32')).toEqual({ command: 'explorer.exe', args: ['/select,', 'C:\\a\\b.txt'] })
+  })
+
+  it('linux: `xdg-open` opens the containing directory (no common select protocol)', () => {
+    expect(revealCommand('/a/b.txt', 'linux')).toEqual({ command: 'xdg-open', args: ['/a'] })
+    expect(revealCommand('/', 'linux')).toEqual({ command: 'xdg-open', args: ['/'] })
+  })
+})
+
+describe('urlCommand', () => {
+  it('darwin: `open <url>` launches the registered protocol handler', () => {
+    expect(urlCommand('vscode://file/x', 'darwin')).toEqual({ command: 'open', args: ['vscode://file/x'] })
+  })
+
+  it('win32: rundll32 url.dll,FileProtocolHandler <url>', () => {
+    expect(urlCommand('cursor://file/x', 'win32')).toEqual({
+      command: 'rundll32.exe',
+      args: ['url.dll,FileProtocolHandler', 'cursor://file/x'],
+    })
+  })
+
+  it('linux: `xdg-open <url>` launches the registered protocol handler', () => {
+    expect(urlCommand('zed://file/x', 'linux')).toEqual({ command: 'xdg-open', args: ['zed://file/x'] })
+  })
+})
+
+describe('validateExternalUrl', () => {
+  it('accepts custom-scheme URLs (incl. the SSH-remote form)', () => {
+    expect(validateExternalUrl('vscode://vscode-remote/ssh-remote+dev/home/u/f.ts'))
+      .toBe('vscode://vscode-remote/ssh-remote+dev/home/u/f.ts')
+    expect(validateExternalUrl('myapp://file/{path}')).toBe('myapp://file/{path}')
+  })
+
+  it('rejects http/https (only custom schemes make sense here)', () => {
+    expect(() => validateExternalUrl('https://example.com')).toThrow(SidebarError)
+    expect(() => validateExternalUrl('http://example.com')).toThrow(SidebarError)
+  })
+
+  it('rejects non-URL / non-`scheme://` strings', () => {
+    expect(() => validateExternalUrl('/home/u/f.ts')).toThrow(SidebarError)
+    expect(() => validateExternalUrl('a:file/x')).toThrow(SidebarError)
+    expect(() => validateExternalUrl('')).toThrow(SidebarError)
+  })
+})
+
+describe('launchExternal validation (pre-spawn)', () => {
+  it('rejects relative reveal paths before anything is spawned', () => {
+    expect(() => launchExternal('reveal', 'relative/path')).toThrow(SidebarError)
+  })
+
+  it('rejects invalid URLs before anything is spawned', () => {
+    expect(() => launchExternal('url', 'https://example.com')).toThrow(SidebarError)
+  })
+})
@@ -0,0 +1,111 @@
+/**
+ * The editor's "open with" settings panel: the SSH host row and the custom
+ * editor list (name + URL template + VSCode-family flag, add/remove). Every
+ * edit commits the whole `openWith` blob through the popup's
+ * updatePluginSetting; removing an editor also prunes its pinned id.
+ */
+// @vitest-environment jsdom
+import { beforeAll, afterEach, describe, expect, it, vi } from 'vitest'
+import { createElement } from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { act } from 'react-dom/test-utils'
+import { OpenWithSettings } from '../src/client/open-with-settings.tsx'
+
+;(globalThis as Record<string, unknown>).IS_REACT_ACT_ENVIRONMENT = true
+
+beforeAll(() => {
+  Object.defineProperty(window.navigator, 'language', { value: 'en-US', configurable: true })
+})
+
+interface Harness {
+  container: HTMLDivElement
+  update: ReturnType<typeof vi.fn>
+  unmount: () => void
+}
+
+function mountSettings(rawOpenWith: unknown): Harness {
+  const container = document.createElement('div')
+  document.body.append(container)
+  const root: Root = createRoot(container)
+  const update = vi.fn()
+  act(() => {
+    root.render(createElement(OpenWithSettings, {
+      pluginSettings: { openWith: rawOpenWith },
+      updatePluginSetting: update,
+    }))
+  })
+  return {
+    container,
+    update,
+    unmount: () => { act(() => { root.unmount() }) },
+  }
+}
+
+const baseConfig = {
+  sshHost: 'dev',
+  customEditors: [
+    { id: 'a', name: 'Windsurf', urlTemplate: 'windsurf://file/{path}', isVscodeFamily: false },
+  ],
+  pinned: ['vscode', 'custom:a'],
+}
+
+describe('OpenWithSettings', () => {
+  let harness: Harness
+  afterEach(() => {
+    harness.unmount()
+    document.body.innerHTML = ''
+  })
+
+  it('seeds the SSH host input from the persisted blob and commits edits', () => {
+    harness = mountSettings(baseConfig)
+    const input = harness.container.querySelector<HTMLInputElement>('input:not([type])')
+    expect(input?.value).toBe('dev')
+    // The native value setter (React's value tracker must see the change).
+    const setter = Object.getOwnPropertyDescriptor(HTMLInputElement.prototype, 'value')!.set!
+    act(() => {
+      setter.call(input, 'prod')
+      input!.dispatchEvent(new Event('input', { bubbles: true }))
+    })
+    expect(harness.update.mock.calls[0]?.[0]).toBe('openWith')
+    expect(harness.update.mock.calls[0]?.[1]).toMatchObject({ sshHost: 'prod' })
+  })
+
+  it('adds a custom editor row and commits the extended list', () => {
+    harness = mountSettings(baseConfig)
+    const add = [...harness.container.querySelectorAll<HTMLButtonElement>('button')]
+      .find(button => button.textContent?.trim() === 'Add')
+    expect(add).toBeDefined()
+    act(() => { add!.click() })
+    const blob = harness.update.mock.calls[0]?.[1] as { customEditors: unknown[]; pinned: string[] }
+    expect(blob.customEditors).toHaveLength(2)
+    expect(blob.pinned).toEqual(['vscode', 'custom:a'])
+  })
+
+  it('removes an editor and prunes its pinned id', () => {
+    harness = mountSettings(baseConfig)
+    const remove = harness.container.querySelector<HTMLButtonElement>('button[aria-label="Remove"]')
+    expect(remove).toBeDefined()
+    act(() => { remove!.click() })
+    const blob = harness.update.mock.calls[0]?.[1] as { customEditors: unknown[]; pinned: string[] }
+    expect(blob.customEditors).toHaveLength(0)
+    expect(blob.pinned).toEqual(['vscode'])
+  })
+
+  it('shows the validity hint when a row is incomplete', () => {
+    harness = mountSettings({
+      sshHost: '',
+      customEditors: [{ id: 'x', name: 'Bad', urlTemplate: 'x://file/x', isVscodeFamily: true }],
+      pinned: [],
+    })
+    expect(harness.container.textContent).toContain('are not shown in the menu')
+  })
+
+  it('edits the VSCode-family flag of one row', () => {
+    harness = mountSettings(baseConfig)
+    const checkbox = harness.container.querySelector<HTMLInputElement>('input[type="checkbox"]')
+    expect(checkbox?.checked).toBe(false)
+    act(() => { checkbox!.click() })
+    const blob = harness.update.mock.calls[0]?.[1] as { customEditors: { isVscodeFamily: boolean }[] }
+    expect(blob.customEditors[0]?.isVscodeFamily).toBe(true)
+  })
+})
@@ -0,0 +1,150 @@
+/**
+ * The file tree "open with" pure logic: config parsing (tolerant), target
+ * resolution (built-ins + custom, SSH filtering), URL building (local file
+ * URLs and VSCode-family SSH-remote URLs) and the custom-editor validators.
+ */
+import { describe, expect, it } from 'vitest'
+import {
+  isValidCustomEditor,
+  newCustomEditorId,
+  normalizeUrlPath,
+  openWithSshActive,
+  openWithUrl,
+  parseOpenWithConfig,
+  resolveOpenWithTargets,
+  type CustomEditor,
+  type OpenWithTarget,
+} from '../src/client/open-with.ts'
+
+describe('parseOpenWithConfig', () => {
+  it('returns the defaults for null / non-object / array values', () => {
+    expect(parseOpenWithConfig(null)).toEqual({ sshHost: '', customEditors: [], pinned: [] })
+    expect(parseOpenWithConfig('junk')).toEqual({ sshHost: '', customEditors: [], pinned: [] })
+    expect(parseOpenWithConfig([])).toEqual({ sshHost: '', customEditors: [], pinned: [] })
+  })
+
+  it('keeps structurally valid custom editors (incl. in-progress rows) and drops junk', () => {
+    const config = parseOpenWithConfig({
+      sshHost: 'dev',
+      customEditors: [
+        { id: 'a', name: 'Windsurf', urlTemplate: 'windsurf://file/{path}', isVscodeFamily: false },
+        { id: 'b', name: '', urlTemplate: 'b://file/{path}', isVscodeFamily: true },
+        { id: 'c', name: 'Trae', urlTemplate: 'trae://file/{path}', isVscodeFamily: true },
+        'junk',
+        null,
+        42,
+      ],
+      pinned: ['vscode', 'custom:a', 42, '', 'custom:c'],
+    })
+    expect(config.sshHost).toBe('dev')
+    expect(config.customEditors.map(editor => editor.id)).toEqual(['a', 'b', 'c'])
+    expect(config.pinned).toEqual(['vscode', 'custom:a', 'custom:c'])
+  })
+})
+
+describe('resolveOpenWithTargets', () => {
+  const localCustom: CustomEditor = { id: 'e1', name: 'Windsurf', urlTemplate: 'windsurf://file/{path}', isVscodeFamily: false }
+  const familyCustom: CustomEditor = { id: 'e2', name: 'Zed-like fork', urlTemplate: 'x-zed://file/{path}', isVscodeFamily: true }
+
+  it('lists built-ins first, then custom editors (local mode)', () => {
+    const targets = resolveOpenWithTargets(parseOpenWithConfig({ customEditors: [localCustom] }))
+    expect(targets.map(target => target.id)).toEqual(['explorer', 'vscode', 'cursor', 'zed', 'custom:e1'])
+    expect(targets[0]?.kind).toBe('reveal')
+    expect(targets[1]?.urlTemplate).toBe('vscode://file/{path}')
+  })
+
+  it('excludes incomplete custom-editor rows from the menu (they stay in the blob)', () => {
+    const targets = resolveOpenWithTargets(parseOpenWithConfig({
+      customEditors: [
+        { id: 'e1', name: 'Windsurf', urlTemplate: 'windsurf://file/{path}', isVscodeFamily: false },
+        { id: 'e2', name: '', urlTemplate: 'incomplete://file/{path}', isVscodeFamily: true },
+      ],
+    }))
+    expect(targets.map(target => target.id)).toEqual(['explorer', 'vscode', 'cursor', 'zed', 'custom:e1'])
+  })
+
+  it('drops local-only targets in SSH mode (file manager, Zed, non-VSCode custom)', () => {
+    const config = parseOpenWithConfig({ sshHost: 'dev', customEditors: [localCustom, familyCustom] })
+    const targets = resolveOpenWithTargets(config)
+    expect(targets.map(target => target.id)).toEqual(['vscode', 'cursor', 'custom:e2'])
+  })
+
+  it('prunes unknown pinned ids only when resolving (the parse keeps them)', () => {
+    const config = parseOpenWithConfig({ pinned: ['ghost'] })
+    expect(config.pinned).toEqual(['ghost'])
+    expect(resolveOpenWithTargets(config).map(target => target.id)).toContain('vscode')
+  })
+})
+
+describe('openWithUrl', () => {
+  const targets = resolveOpenWithTargets(parseOpenWithConfig({}))
+  const byId = (id: string): OpenWithTarget => {
+    const target = targets.find(item => item.id === id)
+    if (target === undefined) throw new Error(`no target ${id}`)
+    return target
+  }
+
+  it('builds local file URLs with the raw path (backslashes normalized)', () => {
+    expect(openWithUrl(byId('vscode'), '/home/u/f.ts', parseOpenWithConfig({}))).toBe('vscode://file//home/u/f.ts')
+    expect(openWithUrl(byId('vscode'), 'C:\\Users\\u\\f.ts', parseOpenWithConfig({}))).toBe('vscode://file/C:/Users/u/f.ts')
+    expect(openWithUrl(byId('zed'), '/x/y', parseOpenWithConfig({}))).toBe('zed://file//x/y')
+  })
+
+  it('builds SSH-remote URLs for VSCode-family targets in SSH mode', () => {
+    const config = parseOpenWithConfig({ sshHost: 'dev' })
+    expect(openWithUrl(byId('vscode'), '/home/u/f.ts', config))
+      .toBe('vscode://vscode-remote/ssh-remote+dev/home/u/f.ts')
+    expect(openWithUrl(byId('cursor'), '/home/u/f.ts', config))
+      .toBe('cursor://vscode-remote/ssh-remote+dev/home/u/f.ts')
+  })
+
+  it('keeps the local URL form for non-VSCode-family targets even in SSH mode', () => {
+    // (Such targets are hidden from the SSH menu; the URL builder stays honest.)
+    expect(openWithUrl(byId('zed'), '/x', parseOpenWithConfig({ sshHost: 'dev' }))).toBe('zed://file//x')
+  })
+
+  it('returns undefined for reveal targets and malformed templates', () => {
+    expect(openWithUrl(byId('explorer'), '/x', parseOpenWithConfig({}))).toBeUndefined()
+    const noScheme: OpenWithTarget = { id: 'x', name: '', kind: 'url', urlTemplate: 'not-a-url {path}', isVscodeFamily: false, localOnly: false }
+    expect(openWithUrl(noScheme, '/x', parseOpenWithConfig({}))).toBeUndefined()
+    const noSlash: OpenWithTarget = { id: 'y', name: '', kind: 'url', urlTemplate: 'a:file/{path}', isVscodeFamily: false, localOnly: false }
+    expect(openWithUrl(noSlash, '/x', parseOpenWithConfig({}))).toBeUndefined()
+  })
+
+  it('uses the custom template scheme for SSH URLs of VSCode-family custom editors', () => {
+    const config = parseOpenWithConfig({
+      sshHost: 'dev',
+      customEditors: [
+        { id: 'e', name: 'Fork', urlTemplate: 'myfork://file/{path}', isVscodeFamily: true },
+      ],
+    })
+    const targets = resolveOpenWithTargets(config)
+    expect(openWithUrl(targets[targets.length - 1]!, '/r/f.ts', config))
+      .toBe('myfork://vscode-remote/ssh-remote+dev/r/f.ts')
+  })
+})
+
+describe('helpers', () => {
+  it('normalizeUrlPath converts backslashes to slashes', () => {
+    expect(normalizeUrlPath('a\\b\\c')).toBe('a/b/c')
+  })
+
+  it('openWithSshActive trims the host', () => {
+    expect(openWithSshActive(parseOpenWithConfig({ sshHost: '  ' }))).toBe(false)
+    expect(openWithSshActive(parseOpenWithConfig({ sshHost: ' dev ' }))).toBe(true)
+  })
+
+  it('isValidCustomEditor requires a name, a {path} placeholder and a scheme:// prefix', () => {
+    expect(isValidCustomEditor({ name: 'A', urlTemplate: 'a://file/{path}' })).toBe(true)
+    expect(isValidCustomEditor({ name: '', urlTemplate: 'a://file/{path}' })).toBe(false)
+    expect(isValidCustomEditor({ name: 'A', urlTemplate: 'a://file/x' })).toBe(false)
+    expect(isValidCustomEditor({ name: 'A', urlTemplate: 'a:file/{path}' })).toBe(false)
+  })
+
+  it('newCustomEditorId yields unique non-empty ids', () => {
+    const first = newCustomEditorId()
+    const second = newCustomEditorId()
+    expect(first).not.toBe(second)
+    expect(first.length).toBeGreaterThan(0)
+  })
+})
@@ -28,8 +28,9 @@ beforeAll(() => {
  })
 })
 import { createBetterSidebarService, type BetterSidebarService } from '../src/client/service.ts'
+import type { TabDescriptor } from '../src/client/service.ts'
+import { FeatureSettingsRows, mergePluginSetting, SettingsBody, SideCardSection, type SideCardSectionProps } from '../src/client/SideCardSection.tsx'
 import { SIDEBAR_PREFS_DEFAULTS } from '../src/prefs-shared.ts'
-import { FeatureSettingsRows, mergePluginSetting, SideCardSection, type SideCardSectionProps } from '../src/client/SideCardSection.tsx'

 /** One tab + one viewer + the subagent-style nested toggle under a tab. */
 function mount(): { store: SidebarStore; service: BetterSidebarService } {
@@ -347,3 +348,68 @@ describe('FeatureSettingsRows valueSource (v0.12.0, independent CR fix)', () =>
    expect(html).toContain('checked=""')
  })
 })
+
+describe('SettingsBody rows + custom render panel (open-with seam)', () => {
+  it('renders the declarative rows AND the custom panel when both are declared', () => {
+    const { store, service } = mount()
+    const feature = {
+      id: 'demo',
+      title: () => 'Demo',
+      component: () => null,
+      settings: {
+        toggles: [{
+          key: 'autoOpenSubagent',
+          title: () => 'Auto row',
+          desc: () => 'row description',
+        }],
+        render: () => createElement('div', { 'data-custom-panel': true }, 'custom panel'),
+      },
+    } as unknown as TabDescriptor
+    const html = renderToString(createElement(SettingsBody, {
+      feature,
+      prefs: SIDEBAR_PREFS_DEFAULTS,
+      store,
+      service,
+      onToggle: () => {},
+      onCommit: () => '',
+      onSelectValue: () => {},
+      onPluginToggle: () => {},
+      onPluginCommit: () => '',
+      onPluginSelectValue: () => {},
+      onPluginWrite: () => {},
+      onClose: () => {},
+    }))
+    expect(html).toContain('Auto row')
+    expect(html).toContain('row description')
+    expect(html).toContain('data-custom-panel')
+    expect(html).toContain('custom panel')
+  })
+
+  it('renders ONLY the custom panel when no rows are declared (unchanged behavior)', () => {
+    const { store, service } = mount()
+    const feature = {
+      id: 'demo',
+      title: () => 'Demo',
+      component: () => null,
+      settings: {
+        render: () => createElement('div', { 'data-custom-panel': true }, 'custom panel'),
+      },
+    } as unknown as TabDescriptor
+    const html = renderToString(createElement(SettingsBody, {
+      feature,
+      prefs: SIDEBAR_PREFS_DEFAULTS,
+      store,
+      service,
+      onToggle: () => {},
+      onCommit: () => '',
+      onSelectValue: () => {},
+      onPluginToggle: () => {},
+      onPluginCommit: () => '',
+      onPluginSelectValue: () => {},
+      onPluginWrite: () => {},
+      onClose: () => {},
+    }))
+    expect(html).toContain('custom panel')
+    expect(html).not.toContain('Auto row')
+  })
+})
@@ -188,6 +188,29 @@ describe('sidebar state', () => {
    expect((onlyDiff?.splits as { tabs: SidebarTab[] }).tabs).toEqual([])
  })

+  it('sanitize removes a pane emptied by ephemeral diff tabs', () => {
+    const valid = sanitizeState({
+      panelOpen: true,
+      width: 400,
+      nextTerminal: 1,
+      activePane: 'pane:diff',
+      expanded: [],
+      splits: {
+        kind: 'split',
+        id: 'split:1',
+        dir: 'col',
+        sizes: [0.5, 0.5],
+        children: [
+          { kind: 'leaf', id: 'pane:git', active: 'git', tabs: [{ id: 'git', type: 'git', title: 'Git' }] },
+          { kind: 'leaf', id: 'pane:diff', active: 'd1', tabs: [{ id: 'd1', type: 'diff', title: 'a.ts' }] },
+        ],
+      },
+    })
+    expect(valid?.splits.kind).toBe('leaf')
+    expect((valid?.splits as { id: string; tabs: SidebarTab[] }).id).toBe('pane:git')
+    expect(valid?.activePane).toBe('pane:git')
+  })
+
  it('dedupes the single-instance subagent tab (focuses instead of duplicating)', () => {
    let s = state()
    s = openTabInActivePane(s, { id: 'subagent', type: 'subagent', title: 'Subagents' })
@@ -716,11 +739,11 @@ describe('persisted state sanitization', () => {
    const clean = sanitizeState(corrupted)
    expect(clean).toBeDefined()
    const leaves = allLeaves(clean!.splits)
-    // The first occurrence keeps its id; the repeat gets a fresh unique one
-    // (exact suffix depends on the module-level uid counter, so assert shape).
-    expect(leaves[0]!.id).toBe('pane:1')
-    expect(new Set(leaves.map(leaf => leaf.id)).size).toBe(2)
-    expect(clean!.activePane).toBe(leaves[1]!.id)
+    // The empty first occurrence is pruned; the populated repeat keeps its
+    // fresh unique id and becomes active.
+    expect(leaves).toHaveLength(1)
+    expect(leaves[0]!.id).not.toBe('pane:1')
+    expect(clean!.activePane).toBe(leaves[0]!.id)
    // And an open must land in exactly one pane of the healed tree.
    const opened = openTabInActivePane(clean!, { id: 'editor:/a.ts', type: 'editor', title: 'a.ts', path: '/a.ts' })
    const owners = allLeaves(opened.splits).filter(leaf => leaf.tabs.some(tab => tab.path === '/a.ts'))
@@ -0,0 +1,191 @@
+/**
+ * Tab-strip right-click context-menu tests. Right-clicking a tab takes over
+ * the browser menu (preventDefault) and shows the tab context menu with
+ * exactly four items: close / close others / close to the left / close to
+ * the right. All bulk operations are scoped to the CURRENT pane (the render
+ * time tab snapshot) and reuse the per-tab onClose path, so the target tab
+ * is never closed and the pane never empties mid-loop. The menu items gray
+ * out when there is nothing to close (single tab → close others; leftmost →
+ * close left; rightmost → close right). Opening the menu must not activate
+ * the right-clicked tab.
+ */
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { createElement } from 'react'
+import { createRoot, type Root } from 'react-dom/client'
+import { act } from 'react-dom/test-utils'
+
+// The act() environment flag (React 18.2 reads it before flushing effects).
+;(globalThis as Record<string, unknown>).IS_REACT_ACT_ENVIRONMENT = true
+
+import { TabBar } from '../src/client/TabBar.tsx'
+import type { SidebarTab } from '../src/client/state.ts'
+
+/** Point the browser-language fallback at Chinese so the menu labels assert. */
+function stubZh(): void {
+  Object.defineProperty(globalThis, 'navigator', {
+    value: { language: 'zh-CN' },
+    configurable: true,
+  })
+}
+
+const MENU_LABELS = ['关闭', '关闭其他页签', '关闭左侧页签', '关闭右侧页签']
+
+function mountBar(tabs: SidebarTab[]): {
+  tabEls: HTMLElement[]
+  onClose: ReturnType<typeof vi.fn>
+  onActivate: ReturnType<typeof vi.fn>
+  unmount: () => void
+} {
+  const container = document.createElement('div')
+  document.body.append(container)
+  const onClose = vi.fn()
+  const onActivate = vi.fn()
+  const root: Root = createRoot(container)
+  act(() => {
+    root.render(createElement(TabBar, {
+      paneId: 'pane:1',
+      tabs,
+      active: tabs[0]?.id ?? null,
+      onActivate,
+      onClose,
+      onNewTab: () => {},
+      newTabOptions: [],
+      onDropTab: () => {},
+    }))
+  })
+  const tabEls = [...container.querySelectorAll('[class*="tabList"] > [class*="tab"]')] as HTMLElement[]
+  return {
+    tabEls,
+    onClose,
+    onActivate,
+    unmount: () => {
+      act(() => { root.unmount() })
+      container.remove()
+    },
+  }
+}
+
+function fourTabs(): SidebarTab[] {
+  return [
+    { id: 't1', type: 'editor', title: 'Tab 1' },
+    { id: 't2', type: 'git', title: 'Tab 2' },
+    { id: 't3', type: 'terminal', title: 'Tab 3' },
+    { id: 't4', type: 'browser', title: 'Tab 4' },
+  ]
+}
+
+/** Dispatch a native right-click (contextmenu) and return the event. */
+function rightClick(target: EventTarget): MouseEvent {
+  const event = new MouseEvent('contextmenu', { bubbles: true, cancelable: true, clientX: 120, clientY: 40 })
+  target.dispatchEvent(event)
+  return event
+}
+
+/** The portaled menu rows (empty when the menu is closed). */
+function menuItems(): HTMLElement[] {
+  return [...document.querySelectorAll<HTMLElement>('[role="menuitem"]')]
+}
+
+afterEach(() => {
+  document.body.innerHTML = ''
+  vi.restoreAllMocks()
+})
+
+describe('TabBar right-click context menu', () => {
+  it('opens the four-item menu at the cursor, prevents the browser menu, and does not activate', () => {
+    stubZh()
+    const { tabEls, onActivate, unmount } = mountBar(fourTabs())
+    try {
+      let event: MouseEvent | null = null
+      act(() => { event = rightClick(tabEls[1]!) })
+      expect(event!.defaultPrevented).toBe(true)
+      expect(menuItems().map(item => item.textContent)).toEqual(MENU_LABELS)
+      expect(onActivate).not.toHaveBeenCalled()
+    } finally {
+      unmount()
+    }
+  })
+
+  it('close closes only the target tab and closes the menu', () => {
+    stubZh()
+    const { tabEls, onClose, unmount } = mountBar(fourTabs())
+    try {
+      act(() => { rightClick(tabEls[1]!) })
+      act(() => { menuItems()[0]!.click() })
+      expect(onClose).toHaveBeenCalledTimes(1)
+      expect(onClose).toHaveBeenCalledWith('t2')
+      expect(menuItems()).toHaveLength(0)
+    } finally {
+      unmount()
+    }
+  })
+
+  it('close others closes every tab in the pane except the target, in visual order', () => {
+    stubZh()
+    const { tabEls, onClose, unmount } = mountBar(fourTabs())
+    try {
+      act(() => { rightClick(tabEls[1]!) })
+      act(() => { menuItems()[1]!.click() })
+      expect(onClose.mock.calls.map(call => call[0])).toEqual(['t1', 't3', 't4'])
+      expect(onClose).not.toHaveBeenCalledWith('t2')
+      expect(menuItems()).toHaveLength(0)
+    } finally {
+      unmount()
+    }
+  })
+
+  it('close left closes only the tabs to the left of the target', () => {
+    stubZh()
+    const { tabEls, onClose, unmount } = mountBar(fourTabs())
+    try {
+      act(() => { rightClick(tabEls[2]!) })
+      act(() => { menuItems()[2]!.click() })
+      expect(onClose.mock.calls.map(call => call[0])).toEqual(['t1', 't2'])
+      expect(menuItems()).toHaveLength(0)
+    } finally {
+      unmount()
+    }
+  })
+
+  it('close right closes only the tabs to the right of the target', () => {
+    stubZh()
+    const { tabEls, onClose, unmount } = mountBar(fourTabs())
+    try {
+      act(() => { rightClick(tabEls[1]!) })
+      act(() => { menuItems()[3]!.click() })
+      expect(onClose.mock.calls.map(call => call[0])).toEqual(['t3', 't4'])
+      expect(menuItems()).toHaveLength(0)
+    } finally {
+      unmount()
+    }
+  })
+
+  it('grays out close others on a single tab and close left/right at the strip ends', () => {
+    stubZh()
+    const single = mountBar([
+      { id: 'only', type: 'editor', title: 'Only' },
+    ])
+    try {
+      act(() => { rightClick(single.tabEls[0]!) })
+      const items = menuItems()
+      // The Menu renders each row as a disabled <button role="menuitem">.
+      expect(items.map(item => (item as HTMLButtonElement).disabled)).toEqual([false, true, true, true])
+      // Clicking the disabled row must not close anything.
+      act(() => { items[1]!.click() })
+      expect(single.onClose).not.toHaveBeenCalled()
+    } finally {
+      single.unmount()
+    }
+
+    const four = mountBar(fourTabs())
+    try {
+      act(() => { rightClick(four.tabEls[0]!) })
+      expect(menuItems().map(item => (item as HTMLButtonElement).disabled)).toEqual([false, false, true, false])
+      act(() => { rightClick(four.tabEls[3]!) })
+      expect(menuItems().map(item => (item as HTMLButtonElement).disabled)).toEqual([false, false, false, true])
+    } finally {
+      four.unmount()
+    }
+  })
+})
@@ -0,0 +1,55 @@
+/**
+ * The TabContent memo comparator: geometry/store re-renders of the Sidebar
+ * shell must not reconcile every mounted tab (issue #315), while the fields
+ * a cell's output or callbacks depend on MUST invalidate it. The pane-move
+ * case (review P1): moveTab reuses the SAME tab object when a tab moves
+ * panes, so paneId — not tab identity — is what identifies the move and
+ * must be compared (onOpenDiff closes over the pane id).
+ */
+import { describe, expect, it } from 'vitest'
+import { tabContentCompare, type TabContentMemoKey } from '../src/client/tab-content-memo.ts'
+import type { SidebarTab } from '../src/client/state.ts'
+
+function makeKey(overrides: Partial<TabContentMemoKey> = {}): TabContentMemoKey {
+  return {
+    tab: { id: 'tab:1', type: 'git', title: 'Git' } as SidebarTab,
+    paneId: 'pane:a',
+    sessionId: 'session:1',
+    cwd: '/workspace',
+    visible: true,
+    expanded: [],
+    localeRevision: 'en-US',
+    tabsVersion: 0,
+    ...overrides,
+  }
+}
+
+describe('tabContentCompare', () => {
+  it('skips re-render when nothing render-affecting changed (callback identity alone is ignored)', () => {
+    const key = makeKey()
+    expect(tabContentCompare(key, { ...key })).toBe(true)
+  })
+
+  it('invalidates on a tab moving between panes even though the tab OBJECT is reused (moveTab P1)', () => {
+    const sameTab = { id: 'tab:1', type: 'git', title: 'Git' } as SidebarTab
+    const before = makeKey({ tab: sameTab, paneId: 'pane:a' })
+    const after = makeKey({ tab: sameTab, paneId: 'pane:b' }) // moveTab reinserts the same object
+    expect(before.tab).toBe(after.tab)
+    expect(tabContentCompare(before, after)).toBe(false)
+  })
+
+  it('invalidates on locale switches (copy freshness)', () => {
+    expect(tabContentCompare(makeKey(), makeKey({ localeRevision: 'zh-CN' }))).toBe(false)
+  })
+
+  it('invalidates on tab-registry updates (descriptor refresh)', () => {
+    expect(tabContentCompare(makeKey(), makeKey({ tabsVersion: 1 }))).toBe(false)
+  })
+
+  it('invalidates on visible/expanded/session/cwd changes', () => {
+    expect(tabContentCompare(makeKey(), makeKey({ visible: false }))).toBe(false)
+    expect(tabContentCompare(makeKey(), makeKey({ expanded: ['/workspace'] }))).toBe(false)
+    expect(tabContentCompare(makeKey(), makeKey({ sessionId: 'session:2' }))).toBe(false)
+    expect(tabContentCompare(makeKey(), makeKey({ cwd: '/other' }))).toBe(false)
+  })
+})
@@ -41,7 +41,7 @@
 * Types ship from lib/types (tsc -p tsconfig.build.json), not from tsdown.
 */
 import { readFile } from 'node:fs/promises'
-import { basename, dirname, relative, resolve as resolvePath, sep } from 'node:path'
+import { basename, dirname, join, relative, resolve as resolvePath, sep } from 'node:path'
 import { builtinModules, createRequire } from 'node:module'
 import { fileURLToPath } from 'node:url'
 import type { UserConfig } from 'tsdown'
@@ -67,6 +67,18 @@ const CLIENT_EXTERNALS = [
  '@deepseek-ai/dsh-client-runtime/client',
 ]

+/**
+ * react-icons' exports map lists `require` BEFORE `import`, so the shared
+ * conditionNames resolve the unshakeable CJS entry and the whole icon set
+ * lands in the core bundle (~6.4 MB extra). Pin the two sets the client
+ * uses to their ESM entries, which tree-shake down to the imported icons.
+ */
+const reactIconsRoot = dirname(dirname(require.resolve('react-icons/lib')))
+const REACT_ICONS_ESM_ALIAS = {
+  'react-icons/si': join(reactIconsRoot, 'si/index.mjs'),
+  'react-icons/vsc': join(reactIconsRoot, 'vsc/index.mjs'),
+}
+
 /**
 * Wire/type layers a client bundle may inline (mirror of the official
 * INLINE_SAFE list): browser-safe contract surfaces with no runtime identity
@@ -140,6 +152,7 @@ function clientBundle(pluginId: string, entryFile: string): UserConfig {
    inputOptions: {
      resolve: {
        conditionNames: ['browser', 'import', 'require', 'default'],
+        alias: REACT_ICONS_ESM_ALIAS,
      },
    },
    // External wins for module-table entries; every other dependency inlines.
Author	SHA1	Message	Date
Menghuan1918	d9b8f15d9e	chore(release): 0.15.2 - bump version: package.json / dsh.plugin.json / SIDEBAR_SERVICE_VERSION - README / README_EN: feature tour converted to a table (two screenshots per row, saves space); add v0.15.2 changelog (file-tree open-in-app menu #334, tab context menu #331, diff collapse by default #270, prune empty restored panes #268, hide git windows on Windows #301, untracked files inside new folders #242, toggle/drag per-frame re-render perf #315); community QR codes landed in #325	2026-08-22 23:30:19 +08:00
Atlas Zeng	22a5d372be	feat(editor): 文件树「在应用中打开」子菜单（外部编辑器/图钉固定/SSH 远端/自定义编辑器） (#334 ) * feat(editor): file tree 'open with' submenu (external editors, pin, SSH-remote, custom editors) The file tree right-click menu gains an 'Open with >' submenu with the resource manager (reveal in file manager), VS Code, Cursor and Zed, plus user-defined custom editors (name + URL template + VSCode-family flag). Each submenu row carries a pushpin that promotes the target to a direct top-level menu item. A configurable SSH host (settings: Files card gear) switches VSCode-family openers to <scheme>://vscode-remote/ssh-remote+<host>/<path> and hides host-local targets (file manager / Zed / non-VSCode custom editors). External opens run through the new fenced /sidebar/api/open.external route which spawns the platform opener with an argv array (no shell); the client never navigates raw scheme URLs itself. The settings seam's render panel now appends after the declarative rows instead of replacing them. * feat(editor): polish open-with menu UI — brand icons, pushpin, chevron, row alignment - Submenu rows: the custom label is now a block-level flex row filling the primitives itemLabel, so the pushpin docks at the row's far right (matching the trailing check of every other menu); menu row icons normalized to 16px (DSH native menus use 16, ours were 14). - The submenu parent row gains a right-aligned chevron (the primitives Menu renders no arrow for submenu parents). - Icons via react-icons: codicons VscPin/VscPinned pushpins (replacing the hand-drawn pin), VscFile/VscFolder/VscFolderOpened tree glyphs (replacing the </> file mark), VscLinkExternal for the open-with parent and the browser tab's open-external button (globally), SiCursor/SiZedindustries brand silhouettes; the VS Code mark is inlined from simple-icons@11.0.0 (CC0) as IconVscode16 since later simple-icons releases dropped it. All monochrome currentColor to follow the active skin. - tsdown: pin react-icons si/vsc to their ESM entries via resolve.alias — the package's exports map lists require before import, so the shared conditionNames picked the unshakeable CJS entry and bloated the core bundle by ~6.4 MB; tree-shaken it now adds only ~12 KB.	2026-08-22 23:19:17 +08:00
wangqiongkakaandwangqiong	f36afc0180	feat: collapse diff files by default (#270 ) * feat: collapse diff files by default * feat: expand source diffs by default --------- Co-authored-by: wangqiong <wangqiong@yy.com>	2026-08-22 23:13:35 +08:00
wangqiongkakaandwangqiong	38a3d94410	fix: prune empty restored panes (#268 ) Co-authored-by: wangqiong <wangqiong@yy.com>	2026-08-22 23:11:57 +08:00
Xinchen Lee	71c5413e5c	fix(git): hide spawned git windows on Windows (#301 )	2026-08-22 23:11:27 +08:00
SKXandMenghuan1918	e867e27106	fix(git): 切换未跟踪文件显示模式以支持新文件夹内文件差异 (#242 ) * fix(git): 切换未跟踪文件显示模式以支持新文件夹内文件差异当使用 `git status --untracked-files=normal` 时，新文件夹会被折叠为单条 `?? dir/` 条目，点击后因无法读取目录（`fs.read` 报错 "is a directory"）而无法加载差异。切换至 `--untracked-files=all` 使新文件夹下的每个文件独立显示为一行，并可正常查看差异，与 VSCode 默认行为一致。同时添加回归测试以验证 porcelain 输出格式。 * test(git): 补真实 git 集成测试钉住 status() 的 --untracked-files=all（review feedback） --------- Co-authored-by: Menghuan1918 <menghuan2003@outlook.com>	2026-08-22 23:09:58 +08:00
Atlas Zeng	4148130aac	perf(sidebar): 消除开关/拖拽的每帧 React 重渲染 - 根因：开关过渡期 ResizeObserver→setCenterRect 每帧重渲染整棵 Sidebar；TabContent 无 memo；内部 Divider/文件树 dock 每 pointermove 全量更新；拖拽残余为 `#root` 每帧 reflow（动画固有成本，A/B 实证非回归）。 - 修复：centerRect 改 ref + 底栏 DOM 直写（零 React 渲染）；TabContent memo（显式比较器，locale/registry/paneId 保持新鲜）；新增 frame-batcher 对 Divider/dock 拖拽按帧合并；拖拽期跳过无意义 locate。 - 验证：单测 76 文件 773 通过；`pnpm test:mount` 12/12（含新 toggle-layout e2e：开关过渡底栏逐帧 0.0px 贴合）；4x CPU 节流 A/B：开关 >17ms 帧 collapse 19→6 / expand 24→4~6，p95 21ms→15ms；拖拽不变（非回归）。 - CR（@codex P1）已修复：`moveTab` 复用同一 tab 对象，比较器改显式比较 `paneId`（含回归单测）。 - 本地 DSH Web 实测通过后按用户要求合入。 fixes #315	2026-08-22 22:50:13 +08:00
Atlas Zeng	924f377fa1	Update README.md	2026-08-22 20:12:32 +08:00
Atlas Zeng	d3c0f22345	feat(tab-bar): add right-click close context menu on tabs (#331 ) Right-clicking a tab now takes over the browser menu and shows four close operations scoped to the current pane: - Close - Close Other Tabs - Close Tabs to the Left - Close Tabs to the Right Items gray out when nothing is eligible (single tab / strip ends). Bulk closes reuse the per-tab onClose path, so descriptor onClose callbacks and terminal pty release still run for every close. Labels are i18n'd (zh/en).	2026-08-22 19:57:34 +08:00
Atlas Zeng	67271e54c8	Clean up community section in README Removed commented-out QR code sections for WeChat and QQ from the community section.	2026-08-22 18:00:24 +08:00
Atlas Zeng	9b4240449c	Update README.md (#325 )	2026-08-22 17:59:20 +08:00