Problem with bottom scroll function
 

I've searched the postings here and have not found a solution to this issue.
I am running PT 7.3 le with a DIGI 003 on a windows XP Dell desktop.

Recently I noticed that in my sessions i am not able to scroll right or left in the edit window..

this is getting very annoying since i do a lot of editing within my sessions as like everyone else. Is there a setting or preference that i an over looking here. Please assist. all help is welcome and appreciated. Thanks in advance..