Critical Error: "Internal Lexical error" when using file autocomplete (# or @) in AI Chat moved to a new window

[Mahdi_Matar]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Hello team,
I am consistently encountering a critical “Internal Lexical error” when trying to reference a file in the AI chat after moving the chat panel into a separate window on macOS.
The application crashes specifically during the autocomplete interaction.

Steps to Reproduce

1. Open the AI Chat panel (sidebar or editor tab).

2. Move the AI Chat panel into a new, dedicated window using the “Move into New Window” command.

3. In this new AI Chat window, start typing a file reference using either @ or #.

4. Begin typing the file name (e.g., MY_FILE_…) and wait for the autocomplete/suggestion list to appear.

5. Click Enter to select the suggested file (MY_FILE_CHOSEN) from the autocomplete list.

Expected Behavior

The selected file reference should be accepted into the chat input field, allowing the AI to process or analyze the file.

Screenshots / Screen Recordings

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.0.69
VSCode Version: 1.99.3
Commit: 63fcac100bd5d5749f2a98aa47d65f6eca61db30
Date: 2025-11-07T18:21:29.650Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 24.6.0

Does this stop you from using Cursor

Yes - Cursor is unusable

[deanrie]

Hey, thanks for the report. I can repro it. I’ll pass it to the team.