anchor.diff:  
     void setSelected(TimelineFrameUI frameUI) {
       if (selectedFrame == frameUI) {
  -      frameUI = null;
  +      return;
       }
   
       if (selectedFrame != frameUI) {
  
positive.code:         ..add(frameDetailsContainer = div()
            ..layoutVertical()
            ..flex()
            ..add(<CoreElement>[frameTabNav, frameFlameChart = FrameFlameChart()])
            ..attribute('hidden')),
      ]);
  
  
negative.code:     CoreElement frameDetailsContainer;
      FrameFlameChart frameFlameChart;
  
      // TODO(kenzie): uncomment these tabs once they are implemented.
  //    final PTabNav frameTabNav = PTabNav(<PTabNavTab>[
  //      PTabNavTab('Frame Timeline'),
  //      PTabNavTab('Widget build info'),
  //      PTabNavTab('Skia picture'),
  //    ]);
  
      pauseButton = PButton.icon('Pause recording', FlutterIcons.pause_white_2x)
        ..small()
  