I have installed Ubuntu Server 12.04 beta 2 on VirtualBox under Mac OS X 10.6.8. Runs fine so far.

Now I wanted to run only one GUI app, Firefox, on this small Ubuntu Server installation. I have added xorg and xserver, and installed the current Firefox 12.0 as described in this forum.

Then I run startx and launch firefox. Runs fine so far.

But whenever I click with the mouse pointer into the Firefox menu bar, the relevant menu box (e.g. the „Tools“ menu box“) and try to click a menu item with the mouse pointer, the menu box disappears as soon as the mouse pointer is over the menu box.

This way, I cannot use any menu items with the mouse.

I know that I have installed just very few things for a GUI. My aim is to have a smallest-possible Ubuntu installation which only handles one single GUI app, Firefox.

Any hints what I could have done wrong or missed to install so the mouse pointer doesn’t work correctly in the Firefox menu bar?