Firefox occasionally stops redrawing / freezes under Xfwm
About once per day, Firefox UI stops updating. It is still working, it just doesn't redraw.
My system is Ubuntu, Xorg and Nvidia proprietary drivers. I have the compositor turned on in Xfwm. This problem has been happening for a couple of years. Closest I can narrow it down to is it didn't happen in Xubuntu 20.04 but I think it does in 22.04 and it definitely does in 23.04.
Webrender is disabled in my Firefox, I think. gfx.webrender.all is set to False.
This is an odd bug and difficult to reproduce so the report will be a list of symptoms and observations for now:
- Moving or resizing the Firefox window will cause it to redraw exactly once.
- Restarting Firefox makes the problem go away temporarily.
- Restarting Xfwm also make the problem go away temporarily.
- If there is a Youtube video playing on the current tab, it will continue playing, even though the rest of the window doesn't update.
- The problem seems to happen more often when watching Youtube videos, especially if one is playing in a background tab.
- Sometimes when this happens, the Xfce panel also freezes, especially the volume control applet. Closing Firefox makes this problem go away too.
- Sometimes Firefox will completely freeze after this happens, ie you can no longer interact with it, and attempting to close the window pops up the Xfwm "frozen application" message. This is very rare though.
So I'm not sure if this is a Xfwm problem or a Firefox problem. It is strange that restarting either of them makes the problem go away.
I realise there isn't much to go on here but I will update this bug if I find anything new.