/*
* Create the tree using the model. We use <code>null</code> as the default
* value of the root node. The default value will be passed to
* CustomTreeModel#getNodeInfo();
*/
CellTree tree = new CellTree(model, null);
tree.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED);
// Open the first playlist by default.
TreeNode rootNode = tree.getRootTreeNode();
TreeNode firstPlaylist = rootNode.setChildOpen(0, true);
firstPlaylist.setChildOpen(0, true);
// Add the tree to the root layout panel.
RootLayoutPanel.get().add(tree);