Kontact using 100% of 1 core

[Diederik de Haas <didi.debian@cknow.org>]

Hello,

Kontact is rather frequently (so not always) using 100% of 1 of my CPU cores, 
but I have no idea why. I'm now running the packages from qt-kde.debian.net, but 
I had it also with the packages targetted for Wheezy (ie KDE SC 4.8.4) and 
possibly even before that.

How can I figure out why that is, cq what causing the 100% CPU usage?
It's 'unfortunately' not constantly reproducable, otherwise I would have filed a 
bug, but since it does happen frequently, I do want to look into it.
Just to make sure, it's not akonadi that's causing the CPU usage but kontact 
itself.

Any pointers?

Cheers,
  Diederik