When using Gnome, notification tray icons for KDE-based apps have an annoying black square under them:
I've tried changing the KDE theme from within KDE but this seems to have no effect. The black squares also change somewhat; if a new application adds a notification tray icon, icons that didn't previously have a black square may add one.
How do I fix this? Thanks!
Edit: I think this should go under Mate, not Gnome, as it seems to be a Mate problem.
Edit 2: Turns out this is a problem other people are having, too.