[BUG] Cursor flashes on every screen update (even while typing) in tmux
Status Open
Reported on v2.1.198
Maintainer reply None cached
Activity 4 comments · opened Jul 3, 2026
Preflight Checklist
- [x] I have searched existing issues and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code
What's Wrong?
When using Claude Code v2.1.200 (I didn't see this behaviour in .198), the cursor flashes on every screen update (even as a type). For example, if I type the word "cursor", the cursor blinks 6 times (once for each character). It also rapidly blinks when text is added to the screen.
What Should Happen?
Claude should not interfere with the normal blink rate of the cursor (like it did in older versions).
Error Messages/Logs
None.Steps to Reproduce
My environment:
Windows11 -> Cygwin Mintty -> Cygwin ssh -> Fedora 43 -> Tmux -> claude agents.
Open "claude agents".
Type anything into the input box.
Claude Model
_No response_
Is this a regression?
Yes, this worked in a previous version
Last Working Version
2.1.198 (but I didn't check all versions)
Claude Code Version
2.1.200
Platform
Anthropic API
Operating System
Other Linux
Terminal/Shell
Other
Additional Information
_No response_
4 Comments
I tried running claude (same version:2.1.200) in WSL (windows terminal), both with tmux and without; but I can't reproduce the problem there.
I've confirmed this is a regression between .199 (which does NOT blink the cursor over ssh) and .200 (which does).
I can reproduce this without Cygwin. If I use WSL to connect via SSH, I can get this issues as well.
And I can get it directly from the agents screen. If one of the sessions is working (and thus has that little animation), the cursor on the agents screen blinks rapidly and constantly.
I can only reproduce this now with tmux. When I run outside tmux, I don't get rapid cursor blinking.