[vtkusers] How to let the arrow in vtkPlaneWidget point to the opposite direction?

[Bertwim van Beest]

Folks,

Essentially a repost, but phrased differently.

Is it possible to let the arrow of a vtkPlaneWidget (when in interactive 
mode) point to the opposite (+/-) direction?
I can't find it in the documentation. But when I look into the source 
code of vtkPlaneWidget, it seems that the normal in both the + and - 
direction are constructed, in a symmetrical fashion. Yet I don't 
understand the details why I always see the same direction.


Thanks in advance,
Regards,
Bertwim