[vtkusers] Adding an ImageSlice to one renderer causes the image to disappear from a different renderer?

[David Doria]

> Do not try to share a mapper between multiple renderers.  Some simple
> mappers might work in this kind of configuration, but many will not.
> Create a new mapper and actor for each renderer.
>
>  - David

Yep, that worked. I don't suppose there would be some way to throw an
error/warning if this setup is attempted with a mapper that does not
support being shared?

David