Kubuntu 21.10
Working along, minding my own business when all of a sudden the application I'm in goes dark, like someone dimmed the lights. I can still use the application, and it doesn't affect anything else - as you can see in the attached picture, the taskbar is still nice and bright. Tonight it happened in Freecad, but it's happened in other apps as well, like VSCode or Brave. When I close and restart the app, it goes back to normal.
What's going on? Is this a symptom of something else?
