public Component prepareEditor(int index) {
   Object value = getModel().getElementAt(index);
   boolean isSelected = isSelectedIndex(index);
   Component comp = editor.getListCellEditorComponent(this, value, isSelected, index);
   if (comp instanceof JComponent) {
     JComponent jComp = (JComponent) comp;
     if (jComp.getNextFocusableComponent() == null) {
       jComp.setNextFocusableComponent(this);
     }
   }
   return comp;
 }