Our custom-made ActiveX grid control written in VB6 behaves very strange in MS Access. We have the combobox cell type when a drop-down list is used to edit this type of cells. When the drop-down list is opened, our grid control flickers. After some experiments we detected that the problem occurs because of the MS Access specific behavior - it clears the contents of the entire control every time when the drop-down list is opened or closed.
We use the native Windows combo box lists functionality for our combo lists. This construction works without any problems when we exploit it in VB6 or even MS Office Word/Excel VBA UserForms, but it fails this way in MS Access.
The attached pictures demonstrate what's happening if we do not redraw the grid contents after the list has been opened (we've temporarily blocked the grid update in the VB UserControl_Paint event for this):
Intercepting such system messages as WM_ERASEBKGND does not help in this development environment. It seems, MS Access does something very special we cannot affect or change anyhow.
Are there any other solutions or ideas we can use to overcome this problem?