[BUG] AskUserQuestion popup steals focus mid-typing, causing a duplicate session to spawn

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?

Environment:

• Claude Code VS Code/VSCodium extension, version 2.1.210-linux-x64
• Editor: VSCodium on Linux

Symptom:
While typing a message to Claude Code, if an AskUserQuestion popup opens
around the same time (i.e. the assistant asks a clarifying question while
I'm still typing my next message), a second, entirely new Claude Code
session/tab gets created in the same VS Code window. Whatever I was
typing appears to land in that new, blank session instead of the one I
intended — the new session has no context from the conversation I was
actually having.

Because both sessions are rooted in the same workspace/repo, they then
independently make tool calls (file edits, git branch/checkout
operations, docker commands) against the same files at the same time,
with no awareness of each other. This produced real collisions: both
sessions edited the same source files differently, and one session
fetched/checked out an unrelated branch into the repo, temporarily
making tracked project files (a whole documentation/ directory) disappear
from the working tree, which understandably looked like data loss.

Confirmed via ps aux: two separate extension-hosted claude processes
were running concurrently, each with a different --resume=<session-id>
argument, both timestamped as having started during the same VS Code
session, both with tool-call activity against the same repo directory.

Impact:

• Duplicate, uncoordinated agent sessions editing the same repo
• Wasted work / conflicting edits between the two sessions
• Confusing, alarming apparent "data loss" that was actually just one

session having switched the working tree to a different git branch

• No warning or indication in the UI that a second session had opened

I don't have an exact minimal repro beyond "type a message right as a
question popup appears" - happy to provide more detail if useful.

What Should Happen?

Requested fix (either would resolve this):

1. AskUserQuestion (and other tool-prompt popups) should not be able to

receive/steal keyboard input intended for the main chat compose box,
so a keystroke during that window can't trigger an unrelated action.

1. If a new Claude Code session does get created while one is already

open and active in the same workspace/repo, surface a clear warning
(e.g. "another session is already active here") rather than silently
running both.

Error Messages/Logs

Steps to Reproduce

1. Open a project in VS Code/VSCodium with the Claude Code extension

(v2.1.210) installed, and start a Claude Code chat session.

1. Give Claude a task that runs for a while and involves multiple

back-and-forth turns (so there are several opportunities for it to
respond while you're still typing your next message).

1. Continue typing in the chat input while Claude is composing/sending

its next response - in particular, try typing right around the
moment Claude calls the AskUserQuestion tool and its popup renders.

1. Observe: instead of your keystrokes landing in the existing

conversation's input box, a second, separate Claude Code session/tab
opens in the same VS Code window. The text you were typing appears
to go to this new, contextless session instead of the original one.

1. Confirm two sessions are both live and both rooted in the same

workspace by running, on Linux: ps aux | grep claude - two
claude processes show up, each with a different
--resume=<session-id> argument, both started during the same VS
Code window session.

1. Give both sessions further instructions (or just let the new one

run) - both independently make tool calls (file edits, git
operations, docker commands) against the same repo with no
awareness of each other, causing conflicting edits.

I don't have a fully deterministic minimal repro (e.g. an exact
keystroke or exact timing) - it reproduced for me by ordinary use over
a long working session, correlating specifically with typing while an
AskUserQuestion popup was opening. If it turns out to reproduce with
any popup/tool-prompt rendering (not just AskUserQuestion specifically),
that would be useful to narrow down.

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Code Version: 2.1.210 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

• No custom keybindings are configured anywhere on this machine: neither

Claude Code's own ~/.claude/keybindings.json nor VSCodium's
~/.config/VSCodium/User/keybindings.json exist. This rules out a
personal/custom shortcut conflict as the cause - whatever triggers the
duplicate session happens with fully default keybindings, which
suggests it should reproduce on a stock install rather than being
specific to my configuration.

• Relevant setting: "claudeCode.preferredLocation": "panel" in VSCodium

User settings.json - the extension is configured to open in the panel
area rather than the sidebar. Might matter if this relates to how
panel-hosted webviews handle focus/keyboard events differently from
sidebar views.

• Editor build: VSCodium 1.105.17075 (codium snap package, classic

confinement), not Microsoft's official VS Code build - noting in case
this is specific to the open-source build's Electron/keybinding
defaults.

• No screenshot available - this happened during normal text-based

terminal/chat use, nothing visual to capture at the moment it occurred.