code: function(modelIdentifier) {
              var model = this.get(modelIdentifier);
              parentClass.remove.apply(this, arguments);
              if (model) {
                var trackedIdsWithoutModel = this.getTrackedIds();
                trackedIdsWithoutModel = _.without(trackedIdsWithoutModel, model.id);
                this.trackIds(trackedIdsWithoutModel);
              }
            }
docs: In addition to removing the model from the collection also remove it from the list of tracked ids.
  @param modelIdentifier {*} same duck-typing as Backbone.Collection.get():
  by id, cid, model object with id or cid properties,
  or an attributes object that is transformed through modelId