anchor.diff:        size = const dartlib.Size(100, 100);
       } else {
         size = new dartlib.Size(
  -          SquareElement._size * value.field.width, SquareElement._size * value.field.height);
  +          SquareElement._size * value.field.width + _edgeOffset * 2,
  +          SquareElement._size * value.field.height + _edgeOffset * 2);
       }
     }
   
  
positive.code: 
    void drawOverride(CanvasRenderingContext2D ctx) {
      _updateElements();
      super.drawOverride(ctx);
      _drawTarget(ctx);
    }
  
    void _drawTarget(CanvasRenderingContext2D ctx) {
  
negative.code: class GameElement extends ElementParentImpl {
    static const _edgeOffset = 32;
  
    final bool _targetMode;
    final dartlib.EventHandle _targetChanged;
  
  