At this stage, it isn't possible to always make a window appear on top. This
seems to be application dependant and not OS dependant. A simple example is
that Word doesn't have the capability but Task Manager does. Acrobat Reader
doesn't have this capability but WinZip does. So, maybe the window
(application) that you want to appear on top has the functionality, if not
then not.
Hope this helps,
Franksta.