Control + Click doesn't work in GUI

[chaosphere2112]

I'm using Control + Click (checking using vtkRenderWindowInteractor.GetControlKey()) in the VCS 2D Interaction stuff to drop new markers / text boxes, and it appears that GetControlKey is never returning True/1 when used in the gui.

[chaosphere2112]

Looks like this is because for Qt on Mac, control is the "command" button, not the control button. I'm going to add some logic to cover that case a bit better.

[chaosphere2112]

Left click + control on mac maps to a right click in Qt. Sigh. Ok, just going to add OS specific code in the VCS stuff to mention "Command" if sys.platform == "darwin".