docs: function(dataset){
      arrayRemove(this.sources, dataset);
  
      // remove event listeners from dataset
      if (this.listen.source)
        dataset.removeHandler(this.listen.source, this);
  
      // process removing dataset objects and update member map
      var memberMap = this.members_;
      for (var objectId in dataset.items_)
        memberMap[objectId].count--;
    }