rootContent.add(placeHolder, BorderLayout.NORTH);
final DemoSelectorTreeNode root = new DemoSelectorTreeNode(null,
demoSelector);
final DefaultTreeModel model = new DefaultTreeModel(root);
final JTree demoTree = new JTree(model);
demoTree.addTreeSelectionListener(new TreeSelectionHandler());
JSplitPane rootSplitPane =
new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
new JScrollPane(demoTree), rootContent);
rootSplitPane.setContinuousLayout(true);