New node in JTree not visible

[Lee Feder]

I've spent ages on this problem but to no avail. Hopefully, one of you guys can help me.
I want to allow users to add a node to a JTree. I'm simulating this by using a button that looks at the current selection and adds a new node to it like this -
parentNode.add( childNode );
where parentNode and childNodes are DefaultMutableTreeNodes.
However this node is only ever visible if it was added to a branch that hasn't been expanded yet. Expanded branches don't get the new node.
What do I have to do to make the new node visible in expanded branches?
Lee.

[Lee Feder]

Don't worry, I fixed it.
Here's what the solution was (I can't believe it was so simple).

DefaultTreeModel dtm = (DefaultTreeModel) theTree.getModel();
dtm.nodesWereInserted( parentNode, new int[] { parentNode.getIndex( childNode ) } );

I am a chump!