Desktop app: diff viewer shows stale content after Claude edits files

Summary

In the Claude Code macOS desktop app, the diff viewer does not auto-refresh when Claude edits files that are already displayed in it. The viewer continues to show the pre-edit diff until it is closed and reopened.

Environment

• Platform: Claude Code macOS desktop app
• Diff viewer: the rebuilt one shipped on 2026-04-14

Repro steps

1. In a git repo with existing uncommitted changes to a file, open the diff viewer (⌘⇧D or click the +N -N stats indicator).
2. Keep the diff viewer open.
3. Ask Claude to edit one of the files already shown in the diff viewer.
4. After the edit completes, look at the diff viewer.

Expected

Diff viewer reflects the post-edit state of the file.

Actual

Diff viewer still shows the pre-edit diff. Verified against the on-disk file state via shell (git diff HEAD), which is correct — the issue is purely viewer-side staleness.

Workaround

Closing and reopening the diff viewer (⌘⇧D twice, or dismissing and re-clicking the stats indicator) does refresh it to the correct state.

However, the workaround has annoying side-effects:

• Files that were collapsed in the side pane become uncollapsed again. Any manual collapsing done to focus the view is lost on every refresh.
• Sidepane width is not preserved. The layout resets each time.

Suggested fix

The viewer should subscribe to file-system / git state changes and auto-refresh, or at minimum offer an explicit refresh control that preserves the viewer's current sidepane collapse state and pane layout.