ive seen cinema displays in some of apples promotional videos, and i was just wondering how they work. i thought it copied whats one, lets say your macbook airs screen, onto the cinema display, so you have more spcae to work with. but that doesnt seem to be the case? it looks like you drag windows to the display? sorry.. im a bit of a noob with this. can anybody explain how it works and how to use it? thanks.