Gnome lists all the programs within the "Debian" menu twice.
 

I did a dist-upgrade from stable to testing and now in the Applications menu, the Debian folder that lists all programs installed. Every program listing in there is shown twice, and it makes reading the list of programs looking for a specific one very difficult. I tried an 'update-menus' but it doesn't seem to help.

what magic trick did i miss?

I have this problem on my PC at home. I haven't had a chance to fix it yet, but I saw this thread that describes how: http://www.eglug.org/node/1651

It says you need to delete: ~/.local/share/applications/menu-xdg and then run "update-menus"

The new menu-xdg in unstable fixes this