I had this issue on my own Windows 7 computer as well as a few customers calling to report this issue. After some research I found some blogs from Patrick Roth as well as David Musgrave from Microsoft on this issue and there is a setting that can be added so that GP retains the Scrolling Window Maximum size.
Here is an example of what you might see. Notice the last character in the scrolling window is cut off.
To fix this, log out of Microsoft Dynamics GP. Navigate to the Dex.ini file which is located in the Data folder where Microsoft Dynamics GP is installed. Example my file is located here: C:Program Files (x86)Microsoft DynamicsGP2010Data
Before making a change to this file, right click on the Dex.ini file and make a copy of it. Next, right click on the Dex.ini file and choose edit or open with notepad. Add the highlighted line to your Dex.ini file: MaxSWScrollbarSize=17
Close and Save the Dex.ini file. Launch GP2010 again and check your scrolling windows.