Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
Upon attempting to add a new tab to the Ai pane, no tab appears and a toast pops up with the following error message: “[composerModesService] Failed to register action for mode 70ef67d7-2237-44be-bec7-81ed9d0a1422:”
When attempting to submit a prompt in any window, the enter button moves the cursor to a new line and doesn’t execute the prompt. Clicking the send arrow also does not submit a prompt.
After closing/re-opening Cursor, any attempts at opening a new tab in the Ai pane are now available, but I’m still unable to submit any prompts.
Steps to Reproduce
Any attempt at adding a new tab via the Ai pane will cause the error; any attempt at submitting a prompt in any open tab in the Ai pane will cause the error
Expected Behavior
Ai prompt submits and is handled by appropriate LLM
Operating System
MacOS
Current Cursor Version (Menu → About Cursor → Copy)
Version: 1.7.44
VSCode Version: 1.99.3
Commit: 9d178a4■■■89981b62546448bb32920a8219a5d0
Date: 2025-10-10T15:43:37.500Z (1 day ago)
Does this stop you from using Cursor
Yes - Cursor is unusable