I seem to have turned on a setting that I can't recall how to turn off. When I click the play button to play from the timeline I expect to see the video play in the preview window. When I do this the video starts to play ok but I don't get to see it because the preview window dissapears. It drops down in a way similar to the way the hide taskbar feature of windows operates. How do i restore settings?

Is it also possible to restore all settings?