Unable to override tmux mouse mode in jupyterlab terminal

[saurabhbelsare]

Description

I use tmux with mouse mode (set -g mouse on in .tmux.conf) in my regular terminal (iTerm2 on MacOS). Whenever I need to select some text, I override the mouse mode with the option key as outlined in this stack overflow post.

If I open the jupyterlab inbuilt terminal, and open a tmux session within that terminal, the mouse mode override does not work by using the option key (or by using any of the other options suggested in that stackoverflow post like Fn, Shift, or command). I am hence unable to select any text inside the jupyterlab inbuilt terminal when using tmux.

This problem, however, does not happen when I open a terminal in the Classic Notebook. In a terminal in the classic notebook, I can select by overriding the mouse mode with the option key.

Do you have any idea of why the tmux mouse mode override doesn't work in the jupyterlab terminal, and how should I fix this?

Thank you!

Reproduce

1. Start a tmux session inside my regular terminal app (iTerm2 on MacOS)
2. Select text inside that tmux session with mouse by overriding mouse mode by holding down the option key -> This does work
3. Open jupyterlab.
4. Open a teminal inside jupyterlab
5. Start a tmux session within that terminal.
6. Select text inside that tmux session with a mouse by overriding mouse mode by holding down the option key -> This does not work.
7. Open Classic Notebook in jupyterlab
8. Open a new terminal from the Classic Notebook menu
9. Start a tmux session within that terminal
10. Select text inside that tmux session with mouse by overriding mouse mode by holding down the option key -> This does work.

Expected behavior

Mouse selection by mouse mode override within tmux should work the same for the terminal within the jupyterlab app as it does for my regular terminal app (iTerm2 on MacOS) and the terminal opened from the Classic Notebook in jupyterlab.

Context

• Operating System and version: MacOS Monterey
• Browser and version: Brave Version 1.42.97
• JupyterLab version: 3.4.5

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[krassowski]

@saurabhbelsare would you mind checking if it worked as intended in older versions of JupyterLab (3.1, 3.2 and 3.3)? I wonder if this might be a regression in xterm.js (which was just upgraded to fix another issue, see #12974).

[saurabhbelsare]

Hi @krassowski

I tried with jupyterlab 3.3.4, 3.2.9, and 3.1.19. For all of them, I'm seeing the exact same behaviour as outlined above for 3.4.5. Mouse mode override works in tmux if opened in a Classic Notebook, but not if I open a terminal directly in the main jupyterlab.

[saurabhbelsare]

Hi, I was wondering whether there was any update on this, and whether it would be doable?
Thanks!