Icon problem in the task bar

[Folco]

I use Fedora 13 beta 64 bits, and CB svn 6206.
I use KDE (4.4.2). I use the graphic driver Nouveau, and the mesa-dri-drivers-experimental 7.8 (OpenGL support).

When I launch CB, its icon in the task bar is displayed normally. But after "some time", it has this appearance :

I have talked about that to a KDE maintener, and he said to me that it could be CB which would corrupt its icon. But it could be also a problem with Plasma, or with the driver etc...

If someone had this kind of configuration (KDE 4, Nouveau etc...), , could he give me some feedback about this problem to know if I have to do a bug report to KDE or to the driver dev team ?

Thanx in advance.

BTW -> I didn't notice this problem with any other app...