>I've set ControlSource to the same field as RowSource and it work now. After all these years working with VFP, I'm still confused about the properties of the combobox. Why do we need 2 properties to set the source of a combobox (ControlSource and RowSource)? Why not just one? What's the difference between ControlSource and RowSource?

Setting ControlSource=RowSource is a bad idea.

RowSource determines the contents of the combo, that is, what the list of items is. ControlSource determines where the initial value comes from and where the value is stored as choices are made from the combo. When they're the same, you're going to get weird behavior.

What are you trying to accomplish here?

Tamar