how to get renderer component from currently selected node

I have extended a DefaultTreeCellRenderer class so that I can have
JComboBoxes and editable fields in my JTree's nodes. My problem is that
I'd like to dynamically update the tooltips for each tree node to
display different information and I'm not sure how this is done.

Currently I just call setToolTipText() from within my
getTreeCellRendererComponent(...) method.

But I'd really like to make setToolTipText() calls from within the
valueChanged(TreeSelectionEvent tse) of my class which is extended from
TreeSelectionListener(). I think maybe I just don't know how to get the
treecellrenderer component from the currently selected node so that I
can call setToolTipText() on it.

Any ideas, help much appreciated.

.