@Override
 public void onKeyPress(KeyPressEvent event) {
   // if the key is enter in the search box, search
   if (event.getSource() == searchBox
       && event.getNativeEvent().getKeyCode() == KeyCodes.KEY_ENTER
       && !event.isAnyModifierKeyDown()) {
     // should send the correct sender
     onClick(null);
   }
 }