anchor.diff:  
   @CustomTag('spark-splitter')
   class SparkSplitter extends SparkWidget {
  +  static const _MIN_DRAGGABLE_SIZE = 6;
  +  
     /// Possible values are "left", "right", "up" and "down".
     /// The direction specifies:
     /// 1) whether the split is horizontal or vertical;
  
positive.code:       _draggable.style
            ..bottom = "0"
            ..top = "0"
            ..left = "-3px"
            ..width = "7px";
      }
    }
  
  
negative.code:   }
  
    void _setThickness() {
      final String sizeStr = '${size}px';
      final int draggableSize = math.max(size, _MIN_DRAGGABLE_SIZE);
      final int draggableStart = ((draggableSize - size) / 2).ceil();
      
      if (_isHorizontal) {
        style
            ..height = sizeStr
  