Switching user

[Pierre Gobin]

Hi,

I've reported the bug about xscreensaver which locks the screen when 
switching user (here : 
https://bugs.launchpad.net/ubuntu/+source/xscreensaver/+bug/978215).

However, I have an other bug, and I don't know on which package report 
it. The bug is that when I have two account opened (using switch user), 
I can't stop the system. I have a dialog box which says "System policy 
prevents stopping the system when other users are logged in". It asks me 
my password, but I have not enough time to type it because the dialog 
box disappears after a few seconds. Here is a screenshot : 
http://pix.toile-libre.org/?img=1334081058.png

If someone could help me !

Thanks,
Pierre Gobi