This seems to be a strange problem. Please refer to the attached screenshots. In the menu where I have clicked on Glipper, the menu is hidden behind the window. Only way to see the menu is to minimize all the windows.
Also, in the second screenshot I have clicked on the View Menu, and it doesnt show the menu. However, if I click on the space where the menu would have been, the items are activated. I was able to goto Full screen mode that way!
I also cannot open context menus in any application. But if I press the shortcut key, the action is performed.
I am running Ubuntu 12.04.1 LTS on a Lenovo G570. IIRC, It has been updated on 15th Jan, 830 AM IST.
I was not able to find a bug report or anything, since I was not able to find the right words. Would gladly +1 the bug report if any.