Originally Posted by sandipt
Which desktop environment you are using: kde OR gnome (version also)? desktop effects / compiz is enabled ? We observed this kind of issue with on Kubuntu 11.04 and investigating it as well.
Sorry for getting back so late and thanks for the answer.
here the data:
kde only, version 4.6.3.
Desktop effects are enabled; I've yet to see the same problem with effects disabled.
the distribution is gentoo, so kde is compiled on the same machine.
I've seen similar problem on a very similar installation, speaking of packages (same revision of gentoo) but a fairly different hardware, AMD with 02:00.0 VGA compatible controller: nVidia Corporation C77 [nForce 780a SLI] (rev a2)
(bug report attached). I have desktop disabled now as I have to work on the latter system, but when it happened the desktop effects were active.
I can make, to some extent, experiments if you need more data, no big deal.
Thanks for the answer!