code: protected boolean eventTargetsPopup(NativeEvent event) {
  
          EventTarget target = event.getEventTarget();
          if (Element.is(target)) {
              return getElement().isOrHasChild(Element.as(target));
          }
          return false;
      }
docs: Returns whether the given event targets the popup.<p>
  
  @param event the event to check
  
  @return <code>true</code> if the event targets the popup