scolling to end of protal messing up fields

My portal works fine in displaying data. A problem occurs when the user repeatedly clicks on the down arrow in the scroll bar at the right, after the portal has scrolled to the last entry. After the last entry is reached during the scroll, repeated clicks on the down arrow causes the last field to display garbage and this display is shown in each preceding field above with every repeated click on the down arrow. In another portal, instead of garbage the fields above display the contents of the last field in the porta, again, in the progressively upward fashion. The fields return to their original values when clicking onto them. This occures in portals that allow new records to be made and those that don't.

I have ensured the fields do not overlap the boundry lines in the portal.

My match field is a conconotated calc field for three fields (category, subcategory and client ID number) and the manipulation for theses parameters makes the portal work well. I chose to use a calc field instead of adding the three fields into the relationship (as this is a new feature in 7) so I wouldn't have to make a calc field for each MF that displays the MF & "PPALL" (The all allows the portal to display more then the selected group.) I found that if I had three fields matching and I chose to have the main file MF empty ( the match wouldn't work) so I have to hava a value such as "all" in the main and related files). Either I use a calc field for each of the three MF's or use one calc that incorporates the "all" and the combinations of the three MF's.

The only problem is when scolling down to the end. Any suggested fixes?

Thanks in Advance. "It's never so bad that it couldn't get worse."

PS: No, I haven't upgraded yet but hope to this weekend (if the kids give me just a little bit of time!).