public void addPopup(int x, int y) {
		
		JMenuItem item = new JMenuItem();
		
		JPopupMenu menu = new JPopupMenu();
		if(list.getSelectedValue() == null) {
			item = new JMenuItem("Add");
			item.addActionListener(new ActionListener() {
				public void actionPerformed(ActionEvent arg0) {
					NewVariableEditor varEdit = new NewVariableEditor();
					if(varEdit.getVariable() != null) {
						listModel.add(listModel.getSize() - 1, varEdit.getVariable());
					}
				}
			});
		} else {
			item = new JMenuItem("Remove");
			item.addActionListener(new ActionListener() {
				public void actionPerformed(ActionEvent arg0) {
					listModel.remove(list.getSelectedIndex());
					list.clearSelection();
				}
			});
		}
		menu.add(item);
		menu.show(list, x, y);
	}