TODO:
- MouseOut event alreay exists (MouseOver, MouseOut) for TrackMouse()
- Test suit should be extended to test the GUI itself.  Perhaps with
  Win32::GUITest?
- Is it possible to only load Win32::API if we actually need it?
- Where should we warn about missing functionality?  Module itself
  or test suite or at installation.  Test and installation don't
  seem good for PPM distributions.