I have tried Elementary OS through a DVD and when I had a window (not maximized) after I maximized it and closed it then when I re-opened it there was a weird jumpy behaviour in the dock. The window was like colliding for a moment with the dock and then the dock disappeared (as it should). That is not happening if you maximize the window but only if you re-open it after closing it (after having it maximized). In the first case there is a smooth "transition" and in the second it is pretty weird. Is that a bug? As I have tried it only through a DVD is that happening if you have it installed?