I put a combo on Form A and a combo on Form B. Both combos have ALL appearance-related properties set to Default. When dropped down, one of them has dotted cell/row borders and one has solid line cell/row borders. Also, the column headers on one of them have a 3D look and the other has more of a flat look.
Why are they so different?
Are these on two different machines? It sounds to me like one of them is themed and the other is not. Or maybe this is because of Visual Styles in DotNet. Is EnableVisualStyles being called on one form, but not the other?