docs: function(oldNode){
        var nodes = this.nodes;
        if (arrayRemove(nodes, oldNode))
        {
          this.first = nodes[0] || null;
          this.last = nodes[nodes.length - 1] || null;
          oldNode.groupNode = null;
  
          this.emit_childNodesModified({ deleted: [oldNode] });
        }
  
        if (!this.first && this.autoDestroyIfEmpty)
          this.destroy();
      }