DefaultTreeModel does not properly synchronize deselection state

using tree component like

<tree checkmark="true" multiple="true" model="@

"/>

tree does not properly synchronize de-selection of tree nodes into tree model (if clicking on checkboxes)

Reproduce:

• create a tree using DefaultTreeModel
• select 2 nodes via browser
  -> ((Selectable)tree.getModel()).getSelection() returns 2 nodes
• unselect 1 node by clicking on checkbox
  -> ((Selectable)tree.getModel()).getSelection() returns 2 nodes

please see also attached example code