I upgraded from Ubuntu 10.04 LTS to 12.04 LTS. It's more or less working.
But, Global Menus aren't working, and when I use HUD no results ever appear. (Example: I search for "F" (without the quotes)) and nothing is found in any application (Terminal, Home Folder,...)
I already did:
sudo apt-get install appmenu-gtk appmenu-gtk3 appmenu-qt
Then restarted, but nothing.
I deleted ~/.config, ~/.gnome2, ~/.compiz-1, ~/.icons and a dozen other such directories (obviously not recommended, but whatever...), restarted, and still no change.
I have a NVIDIA GeForce GT 430 and am using the "post release updates" provided by the Additional Drivers panel in System Settings. Maybe this is related?
Uninstalled the drivers mentioned, rebooted using whatever vanilla detection scheme Ubuntu has going on, no change.