vtkDistanceWiget does not seem to work with vtkImageViewer(2)

This issue was created automatically from an original Mantis Issue. Further discussion may take place here.

With the small python example I've attached to this bug report, it seems that the vtkDistanceWidget doesn't work in a vtkImageViewer2.

Start the example, then click anywhere on the image to make the widget appear. Now try to move its endpoints. On my setup (VTK Paraview 3-0-0 branch) the handles jump to the bottom of the image and remain there. No amount of interaction can get them to move.

I've set up the vtkDistanceWidget according to its test in the VTK repo.