I think there is a wrong behavior of CollapsingHeader and TreeNode being clicked. When such an element is unfolded it gets the clicking event not on it self, but on the very last element it contains. It makes impossible to implement a selection in the tree view and many more.
I believe it might be a bug in the vl implementation.
Please have a look into attached document.
Trees and CollapsingHeader bug.vl (25.3 KB)