private void initializeTree() {
		ArrayList<ClassType> types = dataStore.getTypes();
		tree = new JTree(new DefaultTreeModel(new DefaultMutableTreeNode()));
		
		for (ClassType ct : dataStore.getTypes())	{
			DefaultMutableTreeNode node = new DefaultMutableTreeNode("[" + ct.getShortName() + "] " + ct.getName());
			
			for (Classroom cr : dataStore.getClassrooms()) {
				if(cr.getType() == ct) {
					DefaultMutableTreeNode node2 = new DefaultMutableTreeNode(cr.getName());
					node.add(node2);
				}
			}
			((DefaultMutableTreeNode)(tree.getModel().getRoot())).add(node);
			treenodes.put(ct, node);
		}
		
		for (int i = 0 ; i < tree.getRowCount() ; i++)
			tree.expandRow(i);
		
		tree.setRootVisible(false);
		
		scrollPane = new JScrollPane(tree);
		splitPane.setLeftComponent(scrollPane);
		splitPane.setDividerLocation(0.25);
		
		panel.remove(cbType);
		cbType = new JComboBox(types.toArray());
		panel.add(cbType, 5);
	}