public void valueChanged(TreeSelectionEvent e) {
		    DefaultMutableTreeNode node = (DefaultMutableTreeNode)
		    contentTree.getLastSelectedPathComponent();

		    if (node == null)
		    //Nothing is selected.
		    return;

		    Object nodeInfo = node.getUserObject();

		    if(!node.isRoot()){
		    	Engine.gotoSlide(((TreeEntity)nodeInfo).getId());
		    	if(Debug.sectionNav)System.out.println(
		    			((TreeEntity)nodeInfo).getId() );
		    } else {
		    	if(Debug.sectionNav)System.out.println("Clicked on the " +
		    			"root... can't go there");
		    }
	}