1.  What is the proper way to remove a NShape or NGroup from a NDrawingDocument?
2.  What is the proper way to clear out all shapes from  a NDrawingDocument?

I have been using:
mydocument.ActiveLayer.RemoveChild(aShape);
mydocument.ActiveLayer.RemoveAllChildren();

My problem is that in testing with .Net Memory Profiler, I am seeing the number of NGroups continue to grow even though I thought I had removed them.  

They seem to be held by the document.EventSinkService in a field call "|1|||I||" what ever the heck that is.

AM I doing it right?

Thanks in advance.

Jason