[vtkusers] Moving vtkAbstractWidgets to another vtkRenderWindow

[sercani]

Hi folks;
I need to move vtk widgets from one vtkRenderWindow to another one with 
interactions, what is the best way to do it? I tried to add an overlay 
renderer and move them between vtkRenderWindow instances but there had 
been lots of problems, for example when i tried to add a 
vtkDistanceWidget, because of the wrong spacing values of the overlay 
renderer's world coordinates, it couldn't calculate the right distance 
and of course there had been lots of things to do with 
vtkRenderWindowInteractor in this way...There should be an easy way to 
do it, but i couldn't find it out...