Browser automation crashes Cursor when browser tab is undocked

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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Cursor force-quits when the agent uses browser_type or browser_fill to interact with form inputs while the browser tab is undocked (popped out) from the main project window. The same interaction works without issue when the browser tab remains docked.

Steps to Reproduce

  1. Enable Browser Automation (set to “Browser Tab”)
  2. Undock the browser tab from the project window
  3. Navigate to any page with a form input (in my case, a Clerk sign-in form on localhost)
  4. Have the agent type into a form field via browser automation

Expected Behavior

Form input completes without crashing, regardless of whether the browser tab is docked or undocked.

Operating System

MacOS

Version Information

Version: 2.6.18
VSCode Version: 1.105.1
Commit: 68fbec5aed9da587d1c6a64172792f505bafa250
Date: 2026-03-10T02:01:17.430Z
Build Type: Stable
Release Track: Default
Electron: 39.6.0
Chromium: 142.0.7444.265
Node.js: 22.22.0
V8: 14.2.231.22-electron.0
OS: Darwin arm64 25.3.0

Additional Information

Actual Behavior: Cursor force-quits immediately. No crash dump, no Crashpad report, no macOS DiagnosticReport generated.

Does this stop you from using Cursor

No - Cursor works, but with this issue

3

Hey, thanks for the detailed report. The repro steps are very clear.

This is a known issue with the browser tab when it’s undocked into a separate window. Events don’t get routed correctly to the detached browser view, which in your case causes a hard crash during browser_fill or browser_type.

The team is aware of it.

For now, the workaround is simple. Keep the browser tab docked in the main Cursor window when using browser automation. It should work reliably that way.

Let me know if you hit anything else.