editor.addFocusListener(focusListener);
comboBox.addFocusListener(focusListener);
  protected void installListeners()  {    // install combo box's listeners    propertyChangeListener = createPropertyChangeListener();    comboBox.addPropertyChangeListener(propertyChangeListener);    focusListener = createFocusListener();    editor.addFocusListener(focusListener);    itemListener = createItemListener();    comboBox.addItemListener(itemListener);    keyListener = createKeyListener();    comboBox.addKeyListener(keyListener);    // install listeners that listen to combo box model    listDataListener = createListDataListener();    comboBox.getModel().addListDataListener(listDataListener);    // Install mouse and key listeners from the popup.    popupMouseListener = popup.getMouseListener();    comboBox.addMouseListener(popupMouseListener);    popupMouseMotionListener = popup.getMouseMotionListener();    comboBox.addMouseMotionListener(popupMouseMotionListener);    popupKeyListener = popup.getKeyListener();    comboBox.addKeyListener(popupKeyListener);  }