Tutorial2 cannot be run twice in the same instance of LG3D--LG3D has
to be restarted after Tutorial2 is closed.
The first instance of Tutorial2 creates and registers the "Red Ball
Cursor". Apparently, this persists after Tutorial2 exits and an
exception is thrown when another instance of Tutorial2 is launched.
Right now, I'm trying to decide whether or not the complexity of any
fix in the tutorial would outweight the benefits. Ideas?