getActiveObjectIdForRemove() {
    const activeObject = this.getActiveObject();
    const { type, left, top } = activeObject;
    const isSelection = type === 'activeSelection';

    if (isSelection) {
      const group = new fabric.Group([...activeObject.getObjects()], {
        left,
        top,
      });

      return this._addFabricObject(group);
    }

    return this.getObjectId(activeObject);
  }
Returns the object ID to delete the object.
@returns {number} object id for remove