How to tmux an X11 GUI application so that it can persist through session detach and client disconnection?

The solution is to use xpra in addition to tmux.

Firstly, add the following 4 lines to your $HOME/.profile

alias xp_start='xpra start :100  --start-child=xterm --start-via-proxy=no --opengl=yes'
alias xp_list='xpra list'
alias xp_stop='xpra stop :100'
alias xp_attach='xpra attach :100'

 

To run an X11 app that persist through sessions:

0. SSH (with X11 tunneling, i.e., -X or -Y) into your server containing <your-x11-app>

1. create a new virtual xpra session, run xp_start

2. enter any tmux session or create a new tmux session, run `tmux a` or `tmux`

3. run the X11 app in tmux session with DISPLAY set to 100, run `DISPLAY=:100 <your-x11-app>`

4. inside tmux, attach the xpra session, run xp_attach. This will display the X11 app on your current screen. You can detach the xpra session by Ctrl+C. Detaching the tmux session or SSH disconnection will auto detach the xpra session as well.

Working Principle:

Xpra works by creating a virtual display (with number 100 in this example), then running <your-x11-app> on this virtual display. Since this is a virtual display, all apps running inside it will not be killed due to disconnection or session detach (unless you manually stop the display by xp_stop). When you attach this display :100, all x11-apps running inside this display will be shown on your screen, and they will persist through sessions.