public void itemStateChanged(ItemEvent e) {
			try {
				Object o = e.getSource();

				if (o instanceof JComboBox) {
					JComboBox btn = (JComboBox) o;

					if (list.getSelectedIndex() != -1) {
						// some func is selected
						Function f = (Function) list.getSelectedValue();

						if (f != null) {
							f.returnType = (Type) retTypes.getSelectedItem();
							program.updateDoc();
							argList.repaint();
							list.repaint();
						}
					}
				}
			} catch (ClassCastException ex) {
			}
		}