vtkMFCWindow: translate to client space
Reported-by: Stilles Taylor
Reported here: https://discourse.vtk.org/t/vtkmfcwindow-in-v8-2-0-for-win32-gui-support-has-an-error-handling-message-wm-mousewheel/1921
Reported-by: Stilles Taylor
Reported here: https://discourse.vtk.org/t/vtkmfcwindow-in-v8-2-0-for-win32-gui-support-has-an-error-handling-message-wm-mousewheel/1921