anchor.diff:            break;
         }
         e.preventDefault();
  -    } 
  +    }
     }
   
     void _addFetchUrlParam(String name, String value) {
  
positive.code:     * it should then be possible to press letter keys to navigate the options list without
      * opening the selectbox. That's native browser behavior for <select> element and that's
      * what's being emulated here.
      * 
      * Note the use of keypress_stack. If user presses "a" and "b" within 1 second of each other
      * then the stack is going to contain "ab" and we'll be looking for the first option
      * which has display_value that starts with "ab", then setting it as current option
  
negative.code:   Map attribute_callbacks = {
      'default'  : (attr_name, self) => self.attribute_callbacks_collection['write_property_to_dom'](attr_name, self),
      'disabled' : (attr_name, self) {
        if(self.disabled) {
          self.event_locks.add(#any);
          self.behave('disable');
        } else {
          self.behave('enable');
  