Hi Rich,

> by setting the ROWSOURCE to a c:\path\prog.prg and the ROWSOURCETYPE to 4-Query, then it will not scroll as I move the vertical scroll bar.

I can't reproduce this here. I use a query and the listbox scrolls just fine. Maybe you can use the coverage profiler to see if there's some other code running while you move the mouse. If not, there's nothing I know that you could do. Scrolling in the listbox while sliding the scrollbar is handled by VFP and/or Windows.