New chat submission steals focus to Chrome window (macOS Space switch) when Claude in Chrome is paired

Environment

• macOS (Darwin 25.5.0)
• Claude desktop app 1.11847.5 (auto-updated Jun 9)
• Claude in Chrome extension 1.0.75 (auto-updated Jun 4)
• Chrome extension paired since April (no issues until Jun 11)

Summary

Since the Jun 9 desktop app auto-update, pressing Enter on a new chat causes the paired Chrome window to activate, which switches the macOS Space (desktop slides to the Chrome window). This interrupts the user's work on every new chat.

Key evidence

• It happens before any tool call: a PreToolUse hook that logs every tool invocation shows zero browser tool calls at the time of the focus steal, and no permission dialog appears (all screen-affecting browser tools are set to "ask").
• main.log shows the per-session MCP re-attach ('Claude in Chrome' connector) running on each message submission; the focus steal coincides with this handshake (tab context acquisition), not with model tool use.
• All Claude_in_Chrome tools except passive reads are in permissions.ask, so this cannot be blocked or even observed from the permission layer.

Repro

1. Pair the Claude in Chrome extension.
2. Open a new chat in the desktop app (different macOS Space than Chrome).
3. Type anything and press Enter.
4. Chrome window activates; macOS switches Space. Reproduces on every new chat.

Expected

Connector handshake / tab-context acquisition must be fully passive: no window activation, no focus change, no tab creation.

---
Filed via Claude Code on behalf of the user (diagnosis performed in-session).