>It is not just the grid that has the problem. When I run the form again and lose the grid definition, I also lose the definition of the two drop-down combo boxes that are in the same container. Are they subject to the same anomoly?

I've seen some situations when
Combo.Rowsource=""
Combo.Rowsource=Combo.Rowsource
is helpful. I just wonder why did you get so many things at once. Are your controls (grids,combos) based on cursors?