TreeNodeClickedEvent clickedEvent = (TreeNodeClickedEvent) event;
String nodeId = clickedEvent.getNodeId();
contentCtr.displayPage(ureq, nodeId);
} else if (event instanceof TreeNodeModifiedEvent) {
TreeNodeModifiedEvent nodeEvent = (TreeNodeModifiedEvent) event;
String nodeId = nodeEvent.getNodeId();
String newItemTitle = nodeEvent.getModifiedValue();
treeCtr.updateNode(nodeId, newItemTitle);
} else if (event.getCommand().equals("New Page")) {
String newIdentifier = treeCtr.addNewHTMLPage();
contentCtr.displayPage(ureq, newIdentifier);