I believe I've actually resolve the issue, but I would like a sanity check on this to make sure this won't cause any issues.
Note* ChecklistFilteredTreeView is a control that contains a RadTreeView, and its accessibly as TreeView
my solution, cast the Treeview's datasource back to the type it was when it was set, which in this case is a BindingList, which exposes the events for change, add a handler for that, to expand the nodes when this event is fired.
Again, does this sound like a sound approach?
var foo = ChecklistFilteredTreeView.TreeView.DataSource
foo.ListChanged += (s, eventargs) =>