Tree: Collapsing from ROOT problem


Something weird is happening and I can’t understand.
I have a tree. I use an AbstractHierarchicalDataProvider for painting the TREE (I attach it).
This is the tree with the nodes expanded:

When I collapse root parent (that contains leafs and items with children), only leafs are collaped, not all the opened items.

As you can see, only the nodes that are directly referenced by the root are collapse. The ones under a node with leafs are still visible.

How can I do for collapsing all the node’s children (leafs and items)?? (3.48 KB)

I have committed a project to github that reproduces the problem.

I would really appreciate your help !!