Bug: input textarea background not rendering correctly in tmux session
Resolved 💬 3 comments Opened Oct 4, 2025 by Waishnav Closed Oct 10, 2025
💡 Likely answer: A maintainer (nornagon-openai, contributor)
responded on this thread — see the highlighted reply below.
What version of Codex is running?
codex-cli 0.44.0
Which model were you using?
_No response_
What platform is your computer?
Kubuntu 22.04
What steps can reproduce the bug?
I'm using tmux (3.2a) with Alacritty. After the recent update, the Codex CLI input textarea where we are prompted to write prompt has a grayish background color. Inside a tmux session that background isn’t applied, but outside tmux it works correctly.
What is the expected behavior?
Background color in the tmux session should work as expected.
What do you see instead?
No background color for the input textarea at all.
Additional information
_No response_
3 Comments
Any chance you could try with tmux 3.4 or newer? https://github.com/tmux/tmux/commit/a41a92744188ec5c8a8d4ddc100ec15b52d04603 is what allows this to work inside tmux.
Thanks for pointing this out. I was on Kubuntu 22.04, where the default tmux version is locked to 3.2a, which explains the issue.
I just compiled tmux 3.4, and the background color now works as expected. Appreciate you sharing this solution!
Note for anyone else experiencing this, I had to update to tmux 3.5 to fix it; 3.4 still had this issue for me.
Also, it's a bad idea to use non-standard colors that aren't fg, bg, and color codes 1-6 for reasons like this. At the very least, something like this should be customizable so users can fix problems like this themselves.