Anyone see panel lockups

Hi again Today's issue was that a couple of people reported the plasma panel had locked up overnight. The clock was stuck at a bit after 9:00pm for one person and a bit after 11:00pm for someone else. I tried stracing plasmashell but there was no strace output, and strace was locked up. I couldn't ^C out of it but a kill without -9 was able to kill it. Restarting plasmashell fixed the panel problem. Anyone else seen this sort of behaviour? Thanks Roderick