VS Code extension: agent file-read preview tabs (✻ [Claude Code]) steal keyboard focus from the tab the user is typing in

Environment

• Claude Code VS Code extension 2.1.235 (also present in 2.1.233/2.1.234 bundles)
• VS Code 1.133.0, Windows 11

Problem

While a Claude Code session is working, the extension surfaces the files the agent is reading in a ✻ [Claude Code] … preview tab. Each time that preview opens or updates, the tab is shown via showTextDocument(doc, { preview: true }) with no preserveFocus option — which defaults to taking focus. The preview tab therefore activates itself and moves keyboard focus, in whatever window the session lives in.

When the user is meanwhile typing (or dictating) into a different tab in that same window — including answering an AskUserQuestion prompt in another Claude Code chat — the caret is yanked out of their input mid-sentence, with no user action.

Verified with an element-level UIA focus trace: focus left an AskUserQuestion "Other" input and landed on the freshly re-revealed ✻ [Claude Code] preview tab while a second session's agent read through several files, with zero clicks in the interval.

Where

In the bundled extension.js, the readonly branch of the openContent flow creates the /temp/readonly/… virtual document and shows it with:

d = await dp.workspace.openTextDocument(g), await dp.window.showTextDocument(d, { preview: !0 })

— no preserveFocus, so it defaults to false and steals focus on every reveal. (The editable branch of the same function does pass { preview: !1, preserveFocus: !0 }, so the fix is precedented three lines down.)

Suggested fix

Pass preserveFocus: true on the agent-driven preview reveals in the openContent path so the preview stays passive; user-initiated opens (clicking a file link in chat) can keep taking focus.

This is the file-tab cousin of the focus-jump issue fixed in 2.1.218 ("Fixed focus jumping between open Claude tabs on its own when a window with several Claude panels is restored or reloaded") and of the preserveFocus inconsistency reported for diff-opens in #77979 — same class, different call site.

Impact

Scales with multi-session use: anyone running a working session and an interactive chat in one window hits this every time the worker reads files while they type. It is especially painful mid-AskUserQuestion, where the stolen caret can silently swallow a typed/dictated answer.