TreeView - Selection Chage

Is there a way to add a listener (or other methods) to subscribe to the changes in TreeView selections?
I’m trying to add an editor outside the tree. (let’s say an edit box)
How can I know when the user selects an item in the TreeView.
Previously I have added some kind of workaround with listeners myself. made some calls from the items, to a derived class of the tree, created a “SelectionListener” added some listeners, etc, etc.
But this time around I’m hoping that I’m missing some built-in functionality.

Maybe the solutions in this thread help out?