Created attachment 121127 [details] Screenshot showing the frozen bottom panel. It shows the wrong time(should be 12:27) and wrong applications SUMMARY A few minutes after launching War Thunder's launcher, the bottom panel freezes. STEPS TO REPRODUCE 1. Install War Thunder - I have it installed directly, and not through Steam, which might be relevant (https://warthunder.com/download/launcherLinux/) 2. Launch WarThunder's launcher (launcher in the installation directory) 3. Leave it running and use a different application - do not start the game 4. Notice the clock has stopped moving OBSERVED RESULT 1. The list of applications on the bottom of the screen(I think that's what the Task Manager is) will stop matching the list of actually open application visible on the Alt+Tab window switch preview. For example, Steam has actually been closed and KInfoCenter opened, and the TaskManager doesn't reflect that. 2. The clock will stop moving. 3. Applets will be shown despite actually being hidden - on the screenshot, I have an update notification after having applied the update EXPECTED RESULT There should be no Task Manager freezes caused by running an application. SOFTWARE/OS VERSIONS Linux/KDE Plasma: Kubuntu 19.04 (available in About System) KDE Plasma Version: 5.15.4 KDE Frameworks Version: 5.56.0 Qt Version: 5.12.2 ADDITIONAL INFORMATION I'm using an Nvidia GPU with the proprietary driver. I've not yet verified if the issue can be replicated after this Optimus laptop is switched to Intel mode. I would be happy to run some tracing problem to figure out what is really going on - this issue takes 5-15 minutes to show up but seems to be 100% replicable. I'm using the default OpenGL 2.0 rendering backend for Plasma. I've not yet verified if switching to the OpenGL 3.1 backend would help.
This shows up in dmesg after the launcher is closed by launching the game itself: [ 2919.401765] show_signal_msg: 8 callbacks suppressed [ 2919.401767] launcher[2251]: segfault at 160 ip 00007f759f3c0a4d sp 00007ffd29768920 error 4 in libc-2.29.so[7f759f37a000+1e1000] [ 2919.401771] Code: e8 08 e7 fd ff 49 83 c5 02 45 0f b7 65 fe 49 89 c7 4c 8d 70 fe 48 85 db 75 10 eb c7 90 48 83 c5 08 48 8b 5d 00 48 85 db 74 b9 <66> 44 3b 23 75 ed 48 8d 7b 02 4c 89 f2 4c 89 ee e8 de e7 fd ff 85
To make matters more interesting, when the WarThunder launcher or the game itself are started again, the panel not only freezes again, but the applications displayed on it are exactly the same as in the first freeze after booting. This is starting to look like plasmashell looses an OpenGL context and isn't able to get it back until the application that "stole" it exits.
*** This bug has been marked as a duplicate of bug 353983 ***