title: Mat-sort with rxjs is not working properly
body: <p>I have the problem with implement mat-sort in mat-table, when source was created from observers stream.</p>
  <p>Simply implementation it via documentation by:</p>
  <pre class="lang-js prettyprint-override"><code>ngAfterViewInit() {
      this.dataSource.sort = this.sort;
  }
  </code></pre>
  <p>is not working properly - always will be sorted only 5 rows on my table.</p>
  <p>I think, my problem is with the proper use it with rxjs connection.</p>
  <p>Unfortunately, after checking another questions/documentation I can't find any idea.</p>
  <p>I generated data source from two observer stream. Also I used for it BehaviourSubject (for initial values), combineLatest and switch map. Table was created properly and working perfectly.</p>
  <p>Also when I added filter (according to angular material design documentation) is working properly. But mat-sort... not (only 5 first rows).</p>
  <pre class="lang-js prettyprint-override"><code>    ngOnInit() {
              this.filters = itemFilters;
              this.idSubject = new BehaviorSubject(this.filters[0]);
              Observable.combineLatest(this.name, this.selectedFilter)
                  .do(_ =&gt; this.items = null)
                  .switchMap(([name, filterIndex]: [Name | null, number]) =&gt; {
                      const item = this.filters[filterIndex];
                      this.namesSubject.next(item.display);
                      return this.itemService.getItems(name);
                  })
                  .subscribe(this.setItems.bind(this), this.setError.bind(this));
          }
  </code></pre>
  <p>Also I tried with Observable.zip - but I think it is also not my case. Any idea/advice will be very valuable.</p>
  <p>I think, I should subscribe sorting method to observable streams. That same problem I have with pagination. Sometimes works, sometimes not.</p>