HanoiInitial, HanoiIntermdiate, Office, OfficeA, OfficeTube

There was a problem whereby if vtkBoxWidget2 and vtkBoxWidget occurred
in the same document then, after the vtkBoxWidget2 link was created,
the vtkBoxWidget link was added into the vtkBoxWidget2 link. This
happened because vtkBoxWidget is a sub-string in vtkBoxWidget2.

 to ClipUnstructuredGridWithPlane