Comment 72 for bug 1987976

(In reply to Robert Mader [:rmader] from comment #42)
> Hm, this pretty much sounds like Gnome-Shell bug around Xwayland-on-demand to me - so maybe a better place for that would be https://gitlab.gnome.org/GNOME/mutter/-/issues (or a Ubuntu bug, in case they ship some custom patches).

...

> Thanks @sourcejedi! I've so far been unable to reproduce this on four different systems with Fedora 36 or Manjaro,

Hi Robert. I got a new reproducer for Firefox, which doesn't use Xwayland. I ran this on my Fedora 36 system, the system that required a quick hand to reproduce with my .desktop file method.

WARNING for people with photosensitive epilepsy. This will cause full-screen flickering.

1. Make sure user X is logged out, or at least not running Firefox.
2. Switch to a text console (ctrl + alt + f6) and log in.
3. `startx /usr/bin/fvwm`
4. Left click on the desktop to open the app menu. Open an xterm.
5. Open a second xterm.
6. In xterm 1, run `while true; do picom; sleep 0.1; killall picom; done`. The screen will now start flickering.
7. In xterm 2, run `firefox`

Result: Firefox doesn't draw anything inside its window, or is completely black.