Enter/Backspace act twice in kitty (not in tmux; TUI2 unaffected)
Open 💬 7 comments Opened Dec 19, 2025 by kvcop
💡 Likely answer: A maintainer (fcoury, contributor)
responded on this thread — see the highlighted reply below.
What version of Codex is running?
codex-cli 0.75.0
What subscription do you have?
Pro
Which model were you using?
_No response_
What platform is your computer?
Linux 6.14.0-37-generic x86_64 x86_64
What issue are you seeing?
- Backspace deletes two characters.
- Enter behaves like it was pressed twice (e.g., edit mode toggles and immediately submits).
What steps can reproduce the bug?
- Run codex CLI in legacy TUI (not TUI2).
- In kitty, press Backspace in the composer.
- Also reproducible with Enter: press Esc twice to edit the previous message, then press Enter to confirm - it submits immediately as if Enter was handled twice.
What is the expected behavior?
- Backspace removes a single character.
- Enter confirms edit or submits once.
Additional information
Summary
In the legacy TUI, some key presses (Backspace and Enter) appear to be processed twice when running inside kitty. This is not reproducible in tmux, and on the same machine TUI2 does not show the issue.
Environment
- Terminal: kitty
- Works correctly in tmux on the same machine.
- TUI2 does not exhibit the issue.
Diagnostics
kitty kitten show-key shows normal codes (no obvious duplication):
Press any keys - Ctrl+D will terminate this program
UNIX send_text
^M \r
^? \x7fNotes / Hypothesis (not confirmed)
It may be related to enhanced keyboard reporting producing duplicate key events (legacy + enhanced) in kitty. Not confirmed - need assistance to identify root cause of this issue.
7 Comments
I have the same issue
@tofunori for now i can suggest for you to use tmux every time you want to run codex. There's another version of tui (tui2), but developer stated that it's not ready yet
I have the same issue with ubuntu24 + wayland, the kitty version is 0.32.2(apt repo latest version).
I tried upgrade my kitty to official latest version 0.45.0 without apt install, this problem is resolved.
@kvcop @tofunori I was able to replicate the exact issue with Kitty 0.32.2:
https://github.com/user-attachments/assets/45bf653c-362a-4a67-a108-4c1d3fb44dcc
And after upgrading to 0.45 the problem no longer occurs:
https://github.com/user-attachments/assets/ae816c96-baaa-46d6-9b89-87817d433815
Can you please confirm that this works with latest Kitty and, if it does, can you please close the issue?
Otherwise feel free to let me know by replying again. Thanks!
Can confirm that this issue does not reproduce on kitty 0.46.2.
I was seeing similar keyboard/input anomalies (Backspace/Enter behavior) on older versions, but after upgrading to kitty 0.46.2 the problem disappeared completely in my setup.
Environment:
Might be worth checking if this was implicitly fixed by changes in kitty’s keyboard/input handling.
Also reproducing on Linux in Kitty with codex-cli 0.118.0.
For me, typing
12345and pressing Backspace once deletes both5and4.Additional notes:
codex --no-alt-screenCtrl+Vthen Backspace inserts a single^?on my side, so raw Backspace input does not appeardoubled
Environment:
I was on kitty 0.32.2 (latest in the Ubuntu 24.04 apt repo) and had the exact double Enter/Backspace behavior in codex.
Upgraded to kitty 0.46.2 via the official installer:
curl -L https://sw.kovidgoyal.net/kitty/installer.sh | sh /dev/stdinThen linked it onto PATH ahead of the apt binary:
ln -sf ~/.local/kitty.app/bin/kitty ~/.local/kitty.app/bin/kitten ~/.local/bin/Fully closed every kitty window, reopened, and the issue is gone. So yeah, if you're on Ubuntu/Debian apt kitty, the distro version is just too old.