SUMMARY I'm using KDE Plasma 6.2.5 on a Fedora Linux 41 notebook. The notebook frequently gets attached to / detached from external monitors (it's my work notebook). It sometimes happens that after attaching a monitor, everything updates correctly except for the window list in the task bar, which remains completely empty. ALT+TAB cycling through open windows still works, it only affects the task bar. The issue can be worked around by switching the "Icons-and-Text Task Manager" to one of the alternatives and back. Not a deal breaker, but quite annoying. STEPS TO REPRODUCE 1. Have a desktop configured to show the Icons-and-Text task manager window list. Enable the option to show only the windows of the current screen in the options. 2. Open a few windows (e.g. a dolphin, text editor, web browser ...) 3. Attach an external monitor (you may have to repeat this a couple of times, it doesn't always happen) OBSERVED RESULT The task list shows no windows and is completely empty, even though there clearly are open windows. EXPECTED RESULT The task list should show the open windows SOFTWARE/OS VERSIONS Linux/KDE Plasma: Fedora 41 KDE Plasma Version: 6.2.5 KDE Frameworks Version: 6.10.0 Qt Version: 6.8.1 ADDITIONAL INFORMATION Notebook is a Lenovo ThinkPad T14s Gen 5.
I am experiencing a similar issue - except it's not triggered by attaching another monitor. Instead it happens after my screen is locked and then after some time (likely monitor goes to standby) unlocked. To workaround the issue I can right click in the area where I expect the icons to be and enter edit mode, then exit right away to display the icons and widget properly. I will upload a screenshot next time it occurs.
After just posting I realized I could probably reproduce by locking my screen, powering down monitor manually, then unlocking my screen. The first time I did this it reproduced the issue. After that I couldn't do it for 3 or 4 times but about the 5th time it reproduced again. Attaching screenshots of missing icons and showing icons in my widget. The act of taking a screenshot with Spectacle caused the icons to show up again. I am not using Fedora, but pretty up-to-date Arch. Version info: Operating System: Arch Linux KDE Plasma Version: 6.2.5 KDE Frameworks Version: 6.10.0 Qt Version: 6.8.2 Kernel Version: 6.13.2-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 20 × 12th Gen Intel® Core™ i7-12700 Memory: 62.5 GiB of RAM Graphics Processor: Mesa Intel® UHD Graphics 770 Manufacturer: Dell Inc. Product Name: Precision 3260 If someone gave me rough area of code (repo, files, etc.) to look - I'd be happy to go debugging and work on a fix.
Created attachment 178330 [details] Showing icons missing after reproducing issue.
Created attachment 178331 [details] showing expected icons
Reproducing when I came in this AM and got this log output in journalctl: ``` plasmashell[2504422]: The cached device pixel ratio value was stale on window update. Please file a QTBUG which explains how to reproduce. ``` I was able to build plasma desktop last night and have started debugging process to narrow down the root cause.
*** This bug has been marked as a duplicate of bug 489086 ***
Re-opening, as apparently this is still happening in Plasma 6.3 despite the visual manifestation looking the same as what was reported in bug 489086, which is fixed in Plasma 6.3.0.
Martin - I think I may have hijacked your bug report. Sorry about that. My issue seems fixed with https://bugs.kde.org/show_bug.cgi?id=489086 but it seems your (original reported) in this ticket is still existing.
I'm not able to reproduce this after a few tries on both 6.3.1 and git-master. Given the intermittent nature of the problem, I'll keep the Icons & Text system tray on my machines and keep an eye out for this.