docs: function(delta){
        events.childNodesModified.call(this, delta);
  
        var array;
        if (array = delta.inserted)
        {
          for (var i = 0, child; child = array[i++];)
          {
            child.groupId_ = child.delegate ? child.delegate.basisObjectId : child.data.id;
            this.map_[child.groupId_] = child;
          }
  
          if (this.dataSource && this.nullGroup.first)
          {
            var parentNode = this.owner;
            var nodes = arrayFrom(this.nullGroup.nodes); // basis.array.from, because nullGroup.nodes may be transformed
            for (var i = nodes.length; i-- > 0;)
              parentNode.insertBefore(nodes[i], nodes[i].nextSibling);
          }
        }
      }