Data Grid Scroll Jumps

[Ray]

This problem has come up before, but I don't remember understanding or 
solving it.

In a data grid with the vScrollBar set to true, scrolling suddenly stops 
working.  Any attempt to scroll through about 100 rows of data simply 
jumps to the end and shows only the last row at the very top of the 
grid.  It doesn't matter whether I use the arrows, drag the scroll tab 
or click in the scroll bar.

This seems to have started yesterday when I upgraded to 7.0.5 and then 
went back to 7.0.2 when 7.0.5 corrupted beyond repair a large stack I've 
been working on for several years.  Is there a 'clean install' of some 
sort that I should have done instead of simply uninstalling 7.0.5 and 
re-installing 7.0.2?

Many thanks,

Ray Horsley
LinkIt! Software