[Cooker] Security issu ?

[tsmets]

When 'su' ing to root (or as any other user), 
I get the followin error when trying to start :
xemacs
<pre>
[root@UBI-XHW02 /opt]# Xlib: connection to ":0.0" refused by server
Xlib: Client is not authorized to connect to Server
 
Initialization error: X server not responding
: ":0.0"
</pre>

I guess this is a security issue ?
Could someone confirm ?

Thomas,