Created attachment 183255 [details] Screenshot SUMMARY There is a rectangular box like panel. It slides to the top and disappears when switched into panel configuration mode and reappears when configuration mode exited. It's inresponsive to left or right click. It's also only appears on the main desktop. It does'n appear on additional virtual desktops. (It's most probably related to Wayland to X11 bridge. Because when Wayland to X11 Bridge closes box disappears and when the bridge starts it reappears.) STEPS TO REPRODUCE 1. Start Wayland to X11 Bridge and observe a rectangular box on the top left of the desktop. 2. 3. OBSERVED RESULT A rectangular box on the top left of the desktop EXPECTED RESULT There shouldn't be such a thing. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Fedora 42, Kernel 6.15.5-200 (Waylan) KDE Plasma Version: 6.4.1, 6.4.2 KDE Frameworks Version: 6.16.0 Qt Version: 6.9.1 ADDITIONAL INFORMATION When I first installed Fedora 42 with Kernel 6.14 it wasn't there. It appeared after some updates but I don't remember after which update it appeared. Back then KDE plasma version was 6.4.1 and continued on 6.4.2
Update 17.07.2025: Today updated to Plasma 6.4.3 and still no change.
It does sound like the root cause of this bug is in the XWayland Video Bridge. I found in bug 478750 that xwaylandvideobridge creates a window that previously had been invisible to the user. There have been changes to the way kwin handles layers, and in Qt, which have probably caused that window to now be visible. Unfortunately, xwaylandvideobridge has been archived and is no longer maintained.