The ViewportControl doesn’t respond to mouse-wheel events the way a typical Rhino viewport does. Instead of adjusting the camera location and target, it changes the lens length. Is this intentional / is there another way to zoom? 
Here’s a short video illustrating the issue. Pan and rotate work nicely, but – as you can see – the mouse wheel isn’t much help for navigation (altering only the lens length). The control’s mouse event overrides don’t appear to be called, so a workaround isn’t obvious (to me). Thoughts?
+1 to this question, how can we mimic the default zoom behavior in a Rhino Viewport (the simple mouse wheel one) on a ViewportControl? Struggling with the same issue.