Hey, thanks for the detailed report. This is a known bug. activeGroup can incorrectly point to the Chat editor group instead of the code editor in Cursor 3.x. There’s already a similar report here: Ctrl+Cmd+Left/Right moves focus to Chat tab and splits Chat editors instead of moving code editor
The team is aware of the issue. There’s no fix yet, but the workaround is to not use Chat as an editor tab and keep it in the sidebar instead. Not ideal, but it avoids the problem.
Let me know if there’s anything else.