Hi,
I'd be happy to try to help, but there are too many unknowns here for me to guess at this point.For example, how are you providing the dropdown for the cell? A ValueList? An UltraDropDown? An UltraComboEditor? An UltraCombo?
And what version of the controls are you using?
Where exactly is the mouse - over the cell? Is the cell in edit mode?
If you could post a small sample project here which demonstrates the problem, I'd be glad to take a look and see if I can figure out what's going on and how to stop it. :)