When my windows are not maximised the title bar disappears and the only way to get hold of the application pane is to Alt + Click and Drag.
I am running Natty with Unity and I have not restarted the machine since experiencing the problem. This is because I have a long running process executing on my machine.
Is there an option I might have accidentally enabled? Or does it sound like some kind of process crash? How can I rectify it?