Plasma crashes when I watch a movie with mplayer in full-screen mode and an email comes in or an event is due. Is this a known bug or should I file a report? This might also be an issue of Kwin/KScreen, perhaps only relevant with single screens (not checked in detail). I'm running most recent Arch Linux with Intel graphics (no tweaks so far, AFAIR).

BTW: Should we still have two Plasma categories here? Otherwise, wouldn't it make sense to call the legacy one P4?

answering the first part: we can only know whether it's a known issue once we see the backtrace