[vtkusers] graphical bug in windows

[Tim Newsham]

Hi,  When using VTK with windows there seems to be a bug in
OTHER windows around the VTK window.  I'm not sure the extent
of it, but it appears to at least interfere with tooltip windows.

I'm running with VTK 4.2.6 (yes, I'm outdated).
OS: Windows XP

   - change to VTK/Examples/Rendering/Python
   - run python Cylinder.py
   - move window so part of the window is under the task
     bar at the bottom of the screen.
   - move mouse over various task bar entries and leave
     mouse there until a tooltip pops up

some of the tooltips show up fine.
some of the tooltips show up slightly garbled
some of the tooltips show up with a much larger
   window, with part of the window left unpainted black

This seems to occur when the window is not near the task bar
as well.

I dont have other OpenGL based programs to test with to see
if this is limited to VTK or not.

Tim N.