SUMMARY *** The option to highlight windows when hovering over tooltips has no effect. *** STEPS TO REPRODUCE 1. Configure Task Manager > Highlight windows when hovering over task tooltips: check 2. Hover over a task and then the task tooltip OBSERVED RESULT Nothing happens EXPECTED RESULT Window gets highlighted SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.24.5 KDE Frameworks Version: 5.94.0 Qt Version: 5.15.4 Kernel Version: 5.17.9-arch1-1 (64-bit) Graphics Platform: X11 ADDITIONAL INFORMATION This only stopped working within the last months or so. The code (src/applets/taskmanager/plugin/backend.cpp:655) makes a DBus call to a method "highlightWindows" of KWin. I 'm not well-versed with DBus and don't quite understand the syntax of the call, but I can't seem to find anything of that name browsing around in qdbus viewer. Does it maybe no longer exist?
It's working for me with current git master on Wayland. I wonder if we backported something wrong, or depended on a newer API in KWin that's not in 5.24.
Strangely it goes on and off; a couple days ago it was working again and I could also find the DBus command for it, then it broke once more and the DBus command was no longer to be found, and today it's working fine again. I have no idea what this might depend on. IIRC I didn't even reboot between one of the times it changed. During the times it is broken, I also noticed that the thumbnail grid in the Alt+Tab task switcher would only show application icons instead of previews. Someone else is having the same issue with the previews in the thumbnails in the task bar: https://www.reddit.com/r/kde/comments/vb54sq/hello_what_setting_do_i_need_to_change_if_i_want/ Could this be related?
It appears the DBus services become unavailable when compositing is disabled after KWin crashed; reenabling the compostior also makes the effects work again..
So I think this issue can be closed as not an actual bug, since it only happens when compositing is disabled which obviously can't work.