In Unity 2D and a multi monitor setup (Ubuntu 11.10), the Buttons for Closing, Minimizing and Maximizing windows are not available on the second screen, if the windows are maximized.
There is also no panel showing on the second screen. So there is no menu available for applications on the second screen.
In 11.04, when an window was in Fullscreen on screen 2 the Close, Min, Max Buttons where available on the top left corner of screen one. If I needed the menu from an application maximized on scrren two, I minimized or better said Centered it, pushed it to the first screen used the menu and returned it on screen two.
Now this seems undoable.