[vtkusers] Draw a 2D rectangle onto a region of the screen

[Dan Lipsa]

Hello vtk users,
Is there a simple way to draw a rectangle onto a region of the screen?

I want to use this to highlight the current view. I have looked at
vtkActor2D but nothing seems appropriate.
I also looked at vtkBorderWidget but this seems more for interaction
rather than simple display.

Thanks a lot!

Dan