Created attachment 177255 [details] screenshot with broken panel display )only one widget visible) Added a second control panel on the lower border. This control panel is only displayed partly after the next login (screenshot 1). If you use the control panel settings (Alt D, ALt S), then the panel re-appears, but only until the next logout/login. Screenshot 1: broken panel Screnshot 2: full panel Deleted .cache for debugging, no change. Re-created panel at different positions: same effect
Created attachment 177257 [details] full panel
Thanks for the bug report. Is that the Icon-Only Task Manager you have in the panel to show the app icons?
Yes. But I tried with different task manager widgets ("Anwendungsmenu"). What you see in the broken screenshot is one of the application widgets, all other icons are invisible. As soon as you open the control panel settings once, the control panel is initialized somehow. From this moment it operates as intended, but only until the next login into the same session. I also checked if it has to to do with the session settings (save session or empty session). There is no interference with that setting.
This is Bug 489086, which is fixed in Plasma 6.3. The tip-off is using "fit content" mode. *** This bug has been marked as a duplicate of bug 489086 ***