/** called when our JTree's nodes are selected. */
void nodeSelected(TreeNode treeNode) {
lastSelected = treeNode;
Node node = jtree.getNode(treeNode);
if (node == null) return;
String xpath = DOMInfoExtractor.getXPath(node);
selectedXPathTextField.setText(xpath);
String message = DOMTreeFull.toString(node);
message += "\r\n";
message += xpath;
setMessage(message);
}