Dropping a child element into a treeviewitem will not add the element as a child of the treeviewitem.

Take the default sample application, look at the 'bound treeview' window and drag all of the children from one parent to another, then once empty, try to drag one of the children back to the original parent.

Exactly what I was searching - to drop ON a TreeViewItem to add it as a child to it, not to put next to it. 1-up for this issue.

Yeah we could really use that, too. For an empty list that's the same.