Is there a way to load up a UXTreeView control with all of the items initially collapsed?

  I'm loading up the whole data structure in an Observable collection, ProductCategories,  in the viewmodel.  It has a collection called SubCategories that I'm binding to the CollectionMemberPath.  All the collections contain the same kind of object.  So categories can have subcategories which in turn can have their own subcategories. 

   I can see that all of the levels are loaded and displayed properly.  The problem is it initially displays with all the branches expanded all the way down the chain. 

Silverlight 4 Project

Web UI Studio 2011 R1

DevForce 6.1