[BUG] @ reference using alt+k hotkey switches claude code conversation tab on visual studio in ubuntu (and adds the reference)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

claude-vscode.insertAtMention throws "Webview is disposed" and shifts editor focus when Claude chat panel is not in the rightmost editor group

Summary

Pressing Alt+K (default keybinding for claude-vscode.insertAtMention) throws Error: Webview is disposed inside the extension's command handler, and visibly causes VSCode focus to jump to a different editor tab instead of inserting an @-reference into the Claude chat input. The bug only manifests when the Claude chat panel is not the active editor in the rightmost editor group.

Environment

• Claude Code extension: anthropic.claude-code 2.1.128 (also reproduced on 2.1.126 — same call sites)
• VSCode: 1.118.1 (commit 034f571df509819cc10b0c8129f66ef77a542f0e), x64
• OS: Pop!_OS 22.04 LTS, kernel 6.8.0-76060800daily20240311-generic, GNOME on X11

Steps to reproduce

1. Open the Claude Code chat as an editor tab in a group that is not the rightmost editor group (e.g. left split of two, or middle group of three).
2. Click into the chat input so it has focus.
3. Press Alt+K.

Expected: an @-mention is inserted at the cursor in the chat input.

Actual: editor focus jumps to a different editor tab; the correct chat input does receive the @. Extension Host log records Error: Webview is disposed. With the chat panel in the rightmost group, the same keystroke works correctly, although the focus seems to switch back then forward.

Keybinding troubleshooter (rules out a binding conflict)

[KeybindingService]: | Resolving alt+[KeyK]
[KeybindingService]: \ From 1 keybinding entries, matched claude-vscode.insertAtMention,
                      when: editorTextFocus, source: user extension Anthropic.claude-code.
[KeybindingService]: + Invoking command claude-vscode.insertAtMention.
An unknown error occurred. Please consult the log for more details.

Extension Host stack trace (2.1.128)

Error: Webview is disposed
	at mN.assertNotDisposed (vs/workbench/api/node/extensionHostProcess.js:642:112415)
	at mN.reveal           (vs/workbench/api/node/extensionHostProcess.js:642:112271)
	at pp.value            (anthropic.claude-code-2.1.128-linux-x64/extension.js:805:1721)
	at T._deliver          (extensionHostProcess.js:403:3244)
	at T._deliverQueue     (extensionHostProcess.js:403:3333)
	at T.fire              (extensionHostProcess.js:403:3667)
	at                     (anthropic.claude-code-2.1.128-linux-x64/extension.js:873:10672)
	at Pg._executeContributedCommand (extensionHostProcess.js:503:48683)
	at Pg.$executeContributedCommand (extensionHostProcess.js:503:49654)
	at i._doInvokeHandler            (extensionHostProcess.js:407:157015)
	at i._invokeHandler              (extensionHostProcess.js:407:156763)
	at i._receiveRequest             (extensionHostProcess.js:407:155545)
	at i._receiveOneMessage          (extensionHostProcess.js:407:154383)
	... (MessagePort delivery frames)

Likely root cause

extension.js:805 calls .reveal() on a webview reference that is already disposed. The handler at extension.js:873 (the insertAtMention command path) appears to be holding a stale reference. The "non-rightmost group" precondition suggests the handler is resolving the target webview by editor-group position rather than by id, and picks the wrong (disposed) one when the live chat panel isn't where it expects.

What Should Happen?

the @ should be placed in the window without changing focus

Error Messages/Logs

Error: Webview is disposed
	at mN.assertNotDisposed (vs/workbench/api/node/extensionHostProcess.js:642:112415)
	at mN.reveal           (vs/workbench/api/node/extensionHostProcess.js:642:112271)
	at pp.value            (anthropic.claude-code-2.1.128-linux-x64/extension.js:805:1721)
	at T._deliver          (extensionHostProcess.js:403:3244)
	at T._deliverQueue     (extensionHostProcess.js:403:3333)
	at T.fire              (extensionHostProcess.js:403:3667)
	at                     (anthropic.claude-code-2.1.128-linux-x64/extension.js:873:10672)
	at Pg._executeContributedCommand (extensionHostProcess.js:503:48683)
	at Pg.$executeContributedCommand (extensionHostProcess.js:503:49654)
	at i._doInvokeHandler            (extensionHostProcess.js:407:157015)
	at i._invokeHandler              (extensionHostProcess.js:407:156763)
	at i._receiveRequest             (extensionHostProcess.js:407:155545)
	at i._receiveOneMessage          (extensionHostProcess.js:407:154383)
	... (MessagePort delivery frames)

Steps to Reproduce

Steps to reproduce

1. Open the Claude Code chat as an editor tab in a group that is not the rightmost editor group (e.g. left split of two, or middle group of three).
2. Click into the chat input so it has focus.
3. Press Alt+K.

Expected: an @-mention is inserted at the cursor in the chat input.

Actual: editor focus jumps to a different editor tab; the correct chat input does receive the @. Extension Host log records Error: Webview is disposed. With the chat panel in the rightmost group, the same keystroke works correctly, although the focus seems to switch back then forward.

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.128

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_