@fdarma said:
Well, I have no idea that such an instance definition existed.
On that topic, a detailed breakdown of how instances and definitions work in SketchUp: http://www.thomthom.net/thoughts/2012/02/definitions-and-instances-in-sketchup/
If you are fresh to SketchUp plugins I recommend you also check out this: http://www.thomthom.net/thoughts/2012/01/golden-rules-of-sketchup-plugin-development/