I have a feeling that this is an 'easy when you know how' question.  There are times when I get the pan and crop window on screen and  the window only partially appears - the area showing Position, Rotation, etc.   I cannot see the actual picture that I want to pan and crop - no amount of dragging or rearranging windows seems to help.  Can anyone tell me why this happens and how to get the complete window back?  
(Occasionally when I do get the complete window, the clip that I want to edit appears as a very small picture that makes it difficult to edit).