Scrolling an open document in the doc window in CS5

[davidh202]

I know this must be simple but cannot figure it out!   

  When I try and scroll a corner of my open document to the center of the document window in CS5 when zoomed out( with the hand tool or the mouse wheel), it locks at the edges and will not move inward any further I can move beyond the edges to the outside of the window. It is sometimes more convenient to be able to work on a zoomed in corner of a document when it is centered in the document window. If I go to the rotate tool and set a slight angle it magically unlocks I can then move the document anywhere in the window at any magnification! Is there a setting that is locking the document at the edge of the screen when zoomed out?

BTW this only happens on my work computer .My computer at home allows me to scroll anywhere whithin the doc window no problem?

 
Thanks, David