[BUG] VW palette conversion to BW on Vista

We have begun testing our application on Vista, so far both VW and our
application work with one exception. The conversion of image pallets to
BW is broken. The following code results in a BW image on VW7.5 Windows
XP SP2; using the same version of VW on Windows Vista Business edition
results in a black rectangle.


(Screen default completeContentsOfArea: Screen default bounds)
convertToPalette: MappedPalette blackWhite


Joerg