No window decorations for single applications

Hey,

On the wiki page http://www.x2go.org/doku.php/wiki:development:x2go-qa I  
found these known issue: "On some servers Qt-applications have no window  
decorations, reason is currently unknown."
I'm running the x2go server on a kubuntu, an openSuse 11.4 and 12.1  
machine and confirm this bug for every of these servers! So for me this  
seems not to be a rare problem. All of the machines come with KDE but on  
suse I also installed lxde. I really would like to help to solve this bug  
but I don't know how. If anyone gives me a hint I could give more  
information about the configurations on the servers.
The decorations are missing at every program I tried, this includes pure  
kde, gtk but also java applications.

Best regards
Fabian