anchor.diff:          return fabric.util.object.extend(toObject.call(this), {
             id: this.id,
             floor: this.floor,
  -          element_type_id: this.element_type_id
  +          element_type_id: this.element_type_id,
  +          modified: this.modified
           });
         };
       })(fabric.Object.prototype.toObject);
  
positive.code:           scaleY: <%= element.scaleY %>,
            opacity: <%= element.opacity %>,
            angle: <%= element.angle %>,
            fill: 0,
            id: <%= element.id %>,
            floor: 1,
            element_type_id: <%= element.element_type_id %>
          })
          .setCoords();
  
  
negative.code:       data : { elements: JSON.stringify(obj) }
      });
    }
  
    canvas.on('object:modified', function(options) {
      options.target.modified = true;
    });
  
  </script>