title: CollectionViewSource does not re-sort on property change
body: <p>I'm binding ItemsControl to CollectionViewSource. Here is code:</p>
  
  <pre><code>this.Trucks = new ObservableCollection&lt;Truck&gt;();
              foreach (var truck in DataRepository.Trucks.Where(t =&gt; t.ReadyDate.Date.Equals(this.Date)))
              {
                  this.Trucks.Add(truck);
              }
  
              this.TrucksSource = new CollectionViewSource { Source = this.Trucks };
              this.TrucksSource.SortDescriptions.Add(new SortDescription("ReadyAddress.Region.RegionNumber", ListSortDirection.Ascending));
              this.TrucksSource.SortDescriptions.Add(new SortDescription("TruckId", ListSortDirection.Ascending));
  </code></pre>
  
  <p>When I initially bind - sorting works. When I add item to ObservableCollection - it is inserted in proper spot, thats good. But when I change property which I sort by - this item is not being "shifted" in a list.</p>
  
  <p><code>ReadyAddress.Region.RegionNumber</code> properly raises INotifyPropertyChanged and I see it in bound fields, but order does not change. Do I expect something that shouldn't happen or there is better way to handle this?</p>