Panel freezing

I'm running Fedora-20 with KDE 4.12 (not quite sure how one defines the KDE version now?) Every hour or so the panel does not take any input, eg I cannot change virtual desktop by clicking on them, although I can change them by eg Ctrl-F3 or Ctrl-F5. I haven't found any way to cure this except to log out and login again. Has anyone else experienced this? There are various other misfeatures allied to this, I think, eg slabs of text get highlighted in a curious way. But the panel freezing is the most obvious symptom. -- Timothy Murphy e-mail: gayleard /at/ eircom.net School of Mathematics, Trinity College, Dublin 2, Ireland