I have this exact same bug in Intrepid and it's reproducible every time. In my case, I don't use Compiz (Desktop Effects) on my regular account, because it interferes with 3D gaming. But I have the proprietary nVidia driver installed, so I assume that, when I start up the Guest session, it defaults to switching on Desktop Effects and therefore starts compiz.
From the Alt-F2 screen, I can run gnome-terminal. Doing "killall gnome-panel" gives me the panels back. And "killall nautilus" restores the ability to get a right-click menu on the desktop.
I have this exact same bug in Intrepid and it's reproducible every time. In my case, I don't use Compiz (Desktop Effects) on my regular account, because it interferes with 3D gaming. But I have the proprietary nVidia driver installed, so I assume that, when I start up the Guest session, it defaults to switching on Desktop Effects and therefore starts compiz.
From the Alt-F2 screen, I can run gnome-terminal. Doing "killall gnome-panel" gives me the panels back. And "killall nautilus" restores the ability to get a right-click menu on the desktop.