Thank you for your post.
This display problem was originally discovered by several of our forum members. You can find the complete thread at:
Refresh Error with Vertical ScrollbarIn essence, this occurs when Page Margins are turned on (under the View menu). Our Development and Software Quality Assurance (Testing) departments are aware of this issue.
The thread highlighted in the response showed that page size is an issue, especially when set to 75%, 150% and 300% whereas 100% works. It also mentioned that the glitch happened when using the scroll bar but not with the scroll wheel on the mouse. Neither one of these "fixes" worked with my computer. My page size has always been 100%, and it happened with both the scroll bar and the wheel. It would temporarily fix itself if I toggled between, say 75% and 100% and back. What seems to work the best was turning off page margins as suggested in the response above.
What frustrates me the most about these forums, is the inability of my pea brain to figure out what to call things so I can find answers in the forums. The title of the so-called fix was "refresh error with vertical scrollbar'. In all my searches, never would I have thought to look under refresh error for what I was calling scrolling error.
It's not a perfect solution, but there is a Known Bug List here in the Report an Issue section of the forum. You can open that thread and use your browser's Find tool to search this list for keywords such as "scroll" to try to find existing bug reports.
Each post in this list contains at least one link you can click to go to the original report thread where Filemaker acknowledged the bug.
It can also be downloaded as a database file from: http://www.4shared.com/file/8orL8apk/FMP_Bugs.html