Qt: Session management error

[Marcel Janssen]

Hi,

Just upgraded to F9 and although I have very little issues, I'm stuck with 
one.

I normally log in as user, than when I want to do something as root I open a 
terminal and use su. However, when I try to open some program it gives some 
authentication issue :

Authentication Rejected, reason : None of the authentication protocols 
specified are supported and host-based authentication failed

How can I configure the system to allow all local users to display apps when I 
use su ?

regards,
Marcel