Java Development Tools

Hi,
Using JDeveloper Version 11.1.1.2.0.
I need to create a tree with a checkbox in each of its nodes. When checking a checkbox, the child components should also be checked automatically, while de-checking a child checkbox the parent should be marked in gray (or something) indicating some of it's childs are checked. This is a very common behaviour in tree components.
I tried with treeSelectionListener to implement 'by hand', but the problem is that when selecting a checkbox that is already selected, does not throw any event.

I tried also with valueChangeListener in checkboxes. The "problem" is that I receive an event for each checkbox in the tree !.

Does anybody know how to implement such behaviour?

An example of what I'm trying to implement is found in the new release (4.0) of apex (http://blog.whitehorses.nl/2010/02/28/oracle-apex-4-0-improved-tree-region/), is there any plan to make something similar in ADF ?

Thanks
Roger B