SUMMARY Trying to fullscreen a video in firefox results in a black screen until you are able to exit. STEPS TO REPRODUCE 1. Open Firefox 2. Play a video on any site (I used YouTube) 3. Attempt to fullscreen the video OBSERVED RESULT You're given a black screen that will stay there until you are able to exit fullscreen EXPECTED RESULT The video going into fullscreen mode. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Fedora 34 KDE Plasma Version: 5.22.5 KDE Frameworks Version: 5.85.0 Qt Version: 5.15.2 ADDITIONAL INFORMATION This is my first bug report, sorry if I did any of this wrong. This problems doesn't happen in Gnome. setting full-screen-api.ignore-widgets to true in about:config somewhat fixes the issue, the top window border is still there though and I don't think its a proper solution. This line is also in my journalctl: Oct 09 15:29:16 fedora kwin_x11[2724]: qt.qpa.xcb: QXcbConnection: XCB error: 3 (BadWindow), sequence: 24833, resource id: 113246216, major code: 18 (ChangeProperty), minor code: 0 I'm 99% sure they are related, as the error happens when I try to fullscreen. Thanks.
Do other things go full screen ok? If so report to FF first.
(In reply to David Edmundson from comment #1) > Do other things go full screen ok? If so report to FF first. Yeah, other things work fine, This issue doesnt happen with Gnome though, so I figured I would report it here. If not i'll file on with FF.
This is X or wayland? If wayland, please share output of `WAYLAND_DEBUG=1 firefox`. We can see what FF asks kwin to do and what we get back.