scroll mouse slow on TS

Hi folks,

I'm running TS on a Windows 2003 server, and I have a couple of remote users
who scan documents into a PDF and want to review them, and when they launch
them (Acrobat Reader 8 installed on TS), the mouse scrolling is incredibly
slow - it seems to take forever to scroll and redraw the screen.
Most of these docs are between 10-20 pages. If they are looking at these
PDF's on their regular desktop, the scrolling is fine.
Any advice where to look? I'm trying to get these users to use TS
exclusively - they get confused/frustrated when they switch tasks between
their local PC and TS - that is why I would like to get this fixed in TS.

Mike