Ok, I get it. Once the Dim o as Object has instanced the object, and you set it to Null, you can not get back to an instanced and uninitialized object.
I was attempting to use the instantiated object as a sort of flag for the activity it manages (in my case drag sorting items in a list) that the drag was active, and when they let go, I would set the drag management object to Null, attempting to indicate for event handlers. But then I could never drag again for a second time. I was attempting to call Initialize to get it going again. It seems clear to me now to leave the object instantiated, and to have a separate boolean flag to indicate the drag is active.
Understanding this pattern I am sure is very basic to the language, and known by all, and I just didn't quite get it. Discussion of this not in any of the books or references. Thank you so much for clarifying for me.