I run firefox with the following command:

firejail --x11=xephy firefox

The command usually opens a firefox window (800x600) that fills the xephyr window (800x600). In this case, the following problems occur.


  • When I click on the hamburger menu, it shows the menu briefly appears and then quickly disappears.
  • When I type "alt" the menu bar at top appears. Then when I type f, the file menu briefly appears then quickly disappears.

However, after I run the command, I can intentionally kill xephyr (by pressing alt-f4). When I run the command again, firefox starts in safe-mode. The firefox in safe-mode would open a window that is smaller than 800x600. In this case, the problem disappears

Somehow setting the height and width of the firefox command as below doesn't solve the problem.

firejail --x11=xephy firefox -width=700 -height=500

The window environment is debian 10 + jwm + xorg.

I start it by startx -- -nolisten local.

1 Answer 1


Probably need to run a window manager in additional to firefox.


firejail --x11 --profile=/etc/firejail/chromium.profile openbox --startup "chromium"

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