anchor.diff:  
     void menuActivateHandler(CustomEvent e, var details) {
       if (details['isSelected']) {
  -      close();
  +      _toggle(false);
       }
     }
   
  
positive.code:     }
    }
  
    void open() => toggle(true);
  
    void close() => toggle(false);
  
    //* Handle the on-opened event from the dropdown. It will be fired e.g. when
    //* mouse is clicked outside the dropdown (with autoClosedDisabled == false).
  
negative.code:   }
  
    //* Toggle the opened state of the dropdown.
    void _toggle(bool inOpened) {
      if (inOpened != opened) {
        opened = inOpened;
        // TODO(ussuri): A temporary plug to make spark-overlay see changes
        // in 'opened' when run as deployed code. Just binding via {{opened}}
        // alone isn't detected and the menu doesn't open.
  