Code cleaning.

src/app/core/service/task-list.service.ts

@@ -4,14 +4,13 @@ import { Task } from "../entity/task";
 import { TaskList } from "../entity/task-list";
 import { StorePersistenceService } from "./store-persistence.service";
 import { v4 as uuidv4 } from 'uuid';
-import { filter, throttleTime } from 'rxjs/operators';
+import { filter } from 'rxjs/operators';
 import { Store } from "../entity/store";
 
 @Injectable({
   providedIn: 'root'
 })
 export class TaskListService {
-  private _activeTaskList: BehaviorSubject<TaskList> = new BehaviorSubject<TaskList>(undefined as unknown as TaskList);
   private _store: BehaviorSubject<Store> = new BehaviorSubject<Store>(undefined as unknown as Store);
 
   constructor(