I thought I would try here first before I go the bug route.
This odd behaviour started seemingly for no reason. I couldn’t link it with updates. A second computer doesn’t have the problem.
When I open system settings the panel on the left has a transparent background. If the window underneath is very cluttered then the panel becomes unusable.
Did I cause this somehow?
Does this happen in a new clean user account on the same computer?
I created user “test” and switched to it. Sytem settings appears normal.
A futher detail - if I scrool the panel or move the window the panel completely fills with garbage.
A further detail - if I scroll the panel or move the window the panel completely fills with garbage.
This suggests that a customization you’ve made to your main user account is triggering the problem. If you’re using any 3rd-party themes or KWin scripts, those would be good places to investigate first.
No themes or scripts. As it happens I had made some changes in system settings regarding notifications. I was actually researching a bug. https://bugs.kde.org/show_bug.cgi?id=508301
I knew the bug I was working on was triggered by notifications but was occurring more frequently than the notifications. I eventually found that it was triggered by selinux permissions in NFS but I wasn’t seeing notifications. This is where it gets weird. After the problem with system settings showed up, I started seeing the notification.
SELinux is preventing ftdc from search access on the directory /var/lib/nfs
selinx is set to permissive.
Reinstalling plasma-systemsettings didn’t help.
Now I find that kdeconnect configuration window has the same problem with transparent backgound.