When I click on the main menu to shut down my laptop, it logs me out instead and shows me the logging in window. I have to select shut down on this window to actually shut down the computer. I'm sorry, I dunno how to tell you which packages are affected, but I'll do whatever you need if you don't observe the same problem, in order to reproduce it.
PS: I didn't notice that I posted it 2 times, my apologies :-(
DistroRelease: Ubuntu 10.10
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100429)
Package: gnome-panel 1:2.30.2-1ubuntu3
ProcVersionSignature: Ubuntu 2.6.35-22.34-generic 126.96.36.199
Uname: Linux 2.6.35-22-generic i686
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare