anchor.diff:        overlayRef.dispose();
       } else {
         _resolvedOverlayRef = overlayRef;
  -      _propagateCssClassToOverlay();
         _disposer
           ..addDisposable(_resolvedOverlayRef)
           ..addStreamSubscription(_resolvedOverlayRef.onVisibleChanged
  
positive.code:       _showModalOverlay(temporary: true);
      }
    }
  
    /// Propagate CSS classes of the host element to the overview element for
    /// integration with Angular CSS shimming.
    void _propagateCssClassToOverlay() {
      var hostClassName = _element.className;
      resolvedOverlayRef.overlayElement.className += ' $hostClassName';
    }
  }
  
negative.code:   @Input()
    set preventInteraction(bool preventInteraction) {
      _resolvedOverlayRef.state.captureEvents = preventInteraction != false;
    }
  
    @override
    void ngAfterViewInit() {
      // Propagate CSS classes of the host element to the overview element for
      // integration with Angular CSS shimming.
      var hostClassName = _element.className;
      resolvedOverlayRef.overlayElement.className += ' $hostClassName';
    }
  
    @override
  