Created attachment 138287 [details] Screenshot of the display and panel setup to reproduce SUMMARY When the tooltip of panel widgets slides between adjacent widgets, it can sometimes cause plasmashell to hang entirely. This might only happen if the tooltip partially extends over to a different display than the panel is on? STEPS TO REPRODUCE 1. Set up two monitors in a "sideways T" configuration and add a panel to the bottom of the horizontal one - as per the screenshot attachment 2. Start the Plasma session in Wayland mode 3. Move the mouse over one of the icons in the System Tray, so that its thumbnail appears 4. Move the mouse to the adjacent Digital Clock widget, so that the thumbnail slides over and changes contents - this time it will also partially show on Display 2. 5. Move the mouse back-and-forth between these two widgets quickly a couple times OBSERVED RESULT After a few back-and-forth slides of the thumbnail, it gets stuck in a glitched state over the digital clock, weirdly truncated and flickering. It also hangs the entire panel - I think even plasmashell itself. Unfortunately I can't take a screenshot either, due to the hang. (Nor a screen recording, as OBS crashes on startup due to a Qt bug, SimpleScreenRecorder doesn't support Wayland yet, etc... :/) EXPECTED RESULT The tooltip always shows the correct contents without glitches, and never causes a hang or a crash. SOFTWARE/OS VERSIONS Operating System: Fedora 34 KDE Frameworks Version: 5.81.0 KDE Plasma Version: 5.21.5 Qt Version: 5.15.2 Kernel Version: 5.11.18-300.fc34.x86_64 Graphics Platform: Wayland ADDITIONAL INFORMATION Doing the reproduction steps has caused temporary graphical glitches of the tooltip on the X11 session as well, but never any hangs.
I think #435747 is related - that might be what I've seen back on X11.
Here is a recording of this bug I made with my phone: https://youtu.be/fcuSgOCUpj4
Additional info: From more experiments, it seems that the multi-monitor setup has nothing to do with it, and it's somewhat specific to the digital clock widget. If (compared to the first screenshot) I move the clock widget to the left side of the System Tray widget, and add something else (like a Dictionary) in its former place on the right edge, then still plasmashell only hangs when showing the tooltip of the Clock. Even though the tooltip is now not extending to the other monitor, and the Clock is not at the end of the Panel. And no matter how hard I try, there is no hang when showing the tooltip of either the System Tray, or the Dictionary. It always happens with that of the Clock. I still get graphical glitches though, with basically any panel widget tooltip, but not hangs.
Also, in en earlier experiment, I kept the widget arrangement as original (Clock on the right end, no Dictionary), but resized the Panel to not extend to the right edge of the main (horizontal) screen. This way, the tooltip of the Clock widget was always entirely on the main display, but it still caused hangs.
Can confirm on Neon Unstable (5.22, git master). Also interesting to note: After the freeze, plasmashell --replace won't work, it shows the new shell on top of the old one, then exits. To recover, you'll have to first kill the old plasmashell process, then run plasmashell.
I just found https://bugs.kde.org/show_bug.cgi?id=422072, and I think this bug is a duplicate of that.
Mmm, you're right! It does look like the same thing. Thanks! *** This bug has been marked as a duplicate of bug 422072 ***