Hi Patrick,
Thanks for the response. Sorry my late reaction, I forgot to subscribe to this bugreport so I never saw the reply.
After my last time resetting Plasma I have decided not to use any desktop widgets at all. Now it seems like the problem is gone. I haven't taken the time to investigate which desktop widgets I was using, but it seems like either one of them caused an issue, or another update of my system fixed this bug.
Thanks, Kasper.
