I think the combobox closing is a bug/quirk of the native VFP combobox. It closes upon the first keystroke that occurs ***while*** the mouse pointer is within the rectangular area of the dropdown list. If the mouse pointer is outside of the dropdown, then keystrokes are incrementally searched and dropdown remains open.

Are you saying that setting the combo's Style to Dropdown List makes the dropdown behave more like real dropdowns should?

I find it odd that VFP comboboxes in the developer interface work "properly", yet the native combobox class that MSoft gave us for runtime do not work the same. SO MUCH FOR OOP AND REUSABILITY :)