Tree t = VisualsForTree.createTree();
p.add(t);
EventReporter<Object, TreeItem> handler = new EventReporter<Object, TreeItem>(
p);
t.addKeyboardListener(handler);
t.addMouseListener(handler);
t.addSelectionHandler(new SelectionHandler<TreeItem>() {
public void onSelection(SelectionEvent<TreeItem> event) {
Window.setTitle("select " + prettyPrint(event.getSelectedItem()));
}