>>>Sorry, don't have an answer for that. Although I would guess it has to do with the way VFP paints forms in the VFP screen.
>>
>>Roi,
>>It has nothing to do with VFP. The WS_EX_LAYERED attribute needs to be set on the window for this function to work. Only top-level forms and forms with the Desktop property set to .T. are capable of having this.
>
>No! It has to do with VFP. This attribute can be set to every window, including controls. I have it tested.
>

Alexander,
Then most likely the controls do not have the WS_CHILD or WS_CHILDWINDOW attribute set making them a top-level window. These attributes are incompatible with the WS_EX_LAYERED attribute.

Check out Spy++ (utility that came with Visual Studio 6) to see what attributes these windows have.