         }
     }
     
-    private func updateFetchRequest() {
+    private func updateFetchRequest() throws {
+        fetchedResultsController.fetchRequest.predicate = makeFetchingPredicate()
+        try fetchedResultsController.performFetch()
+        updateGroupings()
+    }
+    
+    private func makeFetchingPredicate() -> NSPredicate {
         var predicates = [NSPredicate]()
         if let selectedDay = selectedDay {
             predicates.append(Event.predicate(forEventsOccurringOn: selectedDay))

        self.eventGroups = newGroups
    }
    
}

// MARK: - ScheduleController + NSFetchedResultsControllerDelegate

        }
    }
    
    private func fetchQueryableEntities() throws {
        try fetchDays()
        try fetchTracks()
