[vtkusers] Using two vtkSeedWidgets in separate renderers

[David Doria]

I am trying to write a Qt interface with two QVTK widgets, each with a
separate vtkSeedWidget. Each of them works properly separately, but as
soon as I load an image into both of the widgets, the behavior is very
strange. The points are no longer placed under the cursor in either
renderer.

Does anyone have any ideas why that might happen? Here is the code:
https://github.com/daviddoria/InteractiveImageRegistration

Thanks,

David