arrowButton = createArrowButton(); configureArrowButton(); comboBox.add(arrowButton);    listBox = new JList();
popup = createPopup(); listBox = popup.getList();
  protected void installComponents()  {    // create and install arrow button    arrowButton = createArrowButton();    configureArrowButton();    comboBox.add(arrowButton);    // Set list that will be used by BasicComboBoxRender     // in order to determine the right colors when rendering    listBox = new JList();    // set editor and renderer for the combo box. Editor is used    // only if combo box becomes editable, otherwise renderer is used    // to paint the selected item; combobox is not editable by default.     comboBox.setRenderer(createRenderer());    comboBox.setEditor(createEditor());    editor = comboBox.getEditor().getEditorComponent();    // create drop down list of items    popup = createPopup();    comboBox.revalidate();  }