Terminal multiplexer zellij injects random input to input widget on auto-focus

[isd-project]

Have you checked closed issues? https://github.com/Textualize/textual/issues?q=is%3Aissue+is%3Aclosed

• yes

Have you checked against the most recent version of Textual? https://pypi.org/search/?q=textual

• yes

Please give a brief but clear explanation of the issue. If you can, include a complete working example that demonstrates the bug. Check it can run without modifications.

Hey 👋

First, I am cross-posting the bug here for completeness and to learn if there are possible workarounds from the textual site.

If one runs the following input.py example with zellij:

from textual.app import App, ComposeResult
from textual.widgets import Input
from time import sleep


class InputApp(App):
    def compose(self) -> ComposeResult:
        yield Input(placeholder="First Name")
        yield Input(placeholder="Last Name")
        # sleep(0.5)


if __name__ == "__main__":
    app = InputApp()
    app.run()

The input widget receives the input: [2026;2$y, which I assume is an ansi escape code sequence.

However, adding a delay seems to help sometimes and the result is always fixed if a non-input widget is focused during startup.

The issue was first reported here: isd-project/isd#34

and I have also reported issue to zellij here: zellij-org/zellij#3959

It will be helpful if you run the following command and paste the results:

Textual Diagnostics

Versions

Name	Value
Textual	1.0.0
Rich	13.9.4

Python

Name	Value
Version	3.12.8
Implementation	CPython
Compiler	GCC 14.2.1 20241116
Executable	/nix/store/7yn2igqsp8alx4ahlh9a0xf5j6y6ak0p-hello-world-dev-env/bin/python3.12

Operating System

Name	Value
System	Linux
Release	6.12.9-cachyos
Version	#1-NixOS SMP PREEMPT_DYNAMIC Thu Jan 9 12:33:55 UTC 2025

Terminal

Name	Value
Terminal Application	ghostty (1.0.2-72d0855-nix)
TERM	xterm-ghostty
COLORTERM	truecolor
FORCE_COLOR	Not set
NO_COLOR	Not set

Rich Console options

Name	Value
size	width=201, height=62
legacy_windows	False
min_width	1
max_width	201
is_terminal	False
encoding	utf-8
max_height	62
justify	None
overflow	None
no_wrap	False
highlight	None
markup	None
height	None

If you don't have the textual command on your path, you may have forgotten to install the textual-dev package.

Feel free to add screenshots and / or videos. These can be very helpful!

[github-actions]

We found the following entry in the FAQ which you may find helpful:

• How do I center a widget in a screen?

Feel free to close this issue if you found an answer in the FAQ. Otherwise, please give us a little time to review.

This is an automated reply, generated by FAQtory

[willmcgugan]

I suspect this is a bug with Zellij. Could you run your test app with TEXTUAL_DEBUG=1 and paste the keys.log file it will save in your working directory.

[isd-project]

Sure!

---
FEED '\x1b[2026;2$y'
character='\x1b'
sequence='\x1b['
sequence='\x1b[2'
sequence='\x1b[20'
sequence='\x1b[202'
sequence='\x1b[2026'
sequence='\x1b[2026;'
sequence='\x1b[2026;2'
sequence='\x1b[2026;2$'
sequence='\x1b[2026;2$y'
Key(key='escape', character='\x1b', name='escape', is_printable=False, aliases=['escape', 'ctrl+left_square_brace'])
REISSUE '[2026;2$y'
Key(key='left_square_bracket', character='[', name='left_square_bracket', is_printable=True)
Key(key='2', character='2', name='2', is_printable=True)
Key(key='0', character='0', name='0', is_printable=True)
Key(key='2', character='2', name='2', is_printable=True)
Key(key='6', character='6', name='6', is_printable=True)
Key(key='semicolon', character=';', name='semicolon', is_printable=True)
Key(key='2', character='2', name='2', is_printable=True)
Key(key='dollar_sign', character='$', name='dollar_sign', is_printable=True)
Key(key='y', character='y', name='y', is_printable=True)

[willmcgugan]

Ok, it looks like Zellij is generating an invalid sequence. I can see from the first line that it is missing a question mark. It should be sending "\x1b[?2026;2$y"

Suggest you report it upstream, looks like an easy fix. The spec is here:

https://gist.github.com/christianparpart/d8a62cc1ab659194337d73e399004036#feature-detection

[isd-project]

Dang, you are fast.

Thanks! ❤️

[github-actions]

Don't forget to star the repository!

Follow @textualizeio for Textual updates.

[darrenburns]

I PR'd a fix for this to Zellij recently (zellij-org/zellij#3884), so should hopefully be released soon 😄

[isd-project]

Yeah, I saw that. You guys are crazy fast 🚀

PS: Sorry that I didn't find you PR. I did search for textual as a keyword inside of the zellij issue tracker :D