It would be very useful to be able of seeing different pages of the document at the same time in the same window... In office word 2007 you can see at least two different pages placed in different parts of the doc at the same time.

I'm electrical engineer student and I used to study of many books in pdf format. There are times when you need to see different topics of the book placed in opposite sides of it and it's to impractical and slow to look for a different pages as many times as you need..It would be so usefull to see in the same workspace different parts of your document or pdf book at the same time..I would save much time when you are reading a long docs.