[vtkusers] Restricting Spliners?

[Robbie Banks]

How do I restrict a vtkSplineWidget to a given actor?

I have a vtkPlaneSource that has been assigned a Scalar field to show data.
I can create and initialize a vtkSplineWidget on this data, but as soon as I
move the handles, it comes off the data.

Unfortunately, this data is not necessarily on the XY, YZ or XZ plane, so I
can't use the SetProjectionToXAxes(), etc. 

With other widgets, I have used AddProp() on the handle representation to
limit the widget to the actor, but the representation of the handles in the
vtkSplineWidget appears to be private and doesn't give you the option to set
the individual handles to the Prop.

Any thoughts?

I was wondering if you could create a vtkPlaneWidget over the existing actor
and then fix the spliner to this using SetPlaneSource??

Cheers
Robbie