Firejail + tmux: tmux windows are labeled "firejail" instead of the actual application

[jovial-snyder]

Description

This is a continuation of an issue that was closed in 2018 by @chiraag-nataraj with no particular reason (the other issue he mentions discusses a completely different topic that was also never resolved). I am creating this new one because the problem still persists. I can't be the only one who uses tmux and firejail, so I am hoping that someone found a workaround.

Problem: When using firejail inside tmux, the tmux window takes the name "firejail" instead of the actual application executed by firejail:

If this problem is not for firejail to solve, then feel free to close this issue.

Steps to Reproduce

1. Open any terminal emulator
2. Start tmux
3. Start an application with firejail (e.g. firejail ngrok)
4. See that the tmux window title is now labeled "firejail" as long as the application is running
5. Now do the same with other applications in other tmux windows, and you end up with many windows labeled "firejail" instead of the actual application ("ngrok"). See screenshot above. This makes it hard to find a window.

Expected behavior

4. See that the tmux window title is now "ngrok" and not "firejail"

Environment

• Name/version/arch of the Linux kernel (uname -srm): Linux 6.11.0-12-generic x86_64
• Name/version of the Linux distribution (e.g. "Ubuntu 20.04" or "Arch Linux"): Ubuntu 24.10
• Version of Firejail (firejail --version): 0.9.72

[rusty-snake]

Terms to differentiated:

• The title of the Terminal-Emulator X11/Wayland-Window
• The title of the Terminal-Emulator Tab (if supported)
• The name of the tmux window
• The "title" of a tmux window
• The title of the tmux pane

[jovial-snyder]

If anyone ever has this issue, it's easily solved. Just add the following line to your tmux.conf: set -g allow-rename on. I am not entirely sure if that is all that is needed, but I added this to my already customized tmux.conf, and it did the trick. This way, tmux will always display the last command that is executed in a chain of commands, at least this is how I observed the behavior. So if I run now firejail ngrok, the window name is just ngrok.

And sorry for the confusion, the correct description is window name.