title: RX: 'ObservableAsProperty' bound properties are not automatically updated on gui
body: <p>I have a Client <code>MyClient</code> which provides new stati via an <code>IObservable</code>. As described in the documentation (<a href="https://reactiveui.net/docs/handbook/view-models/boilerplate-code" rel="nofollow noreferrer">https://reactiveui.net/docs/handbook/view-models/boilerplate-code</a>) I made a private property of type <code>ObservableAsProperty</code> to get the output of my <code>IObservable</code>. But know my GUI is not updated automatically on changes.</p>
  
  <pre class="lang-cs prettyprint-override"><code>public partial class MainWindow : ReactiveWindow&lt;AppViewModel&gt;
  {
      public MainWindow()
      {
          InitializeComponent();
          ViewModel = App.Container.GetInstance&lt;AppViewModel&gt;();
          this.WhenActivated(r =&gt;
              {
                  this.OneWayBind(ViewModel, viewModel =&gt; viewModel.Status.AoiStatus, view =&gt; view.StatusTxtbl.Text).DisposeWith(r);
              });
      }
  }
  
  public class AppViewModel : ReactiveObject
  {
  
      public IStatus Status { [ObservableAsProperty] get; }
  
      public MyClient Client { get; }
  
      public AppViewModel(MyClient client)
      {
          Client = client;
          Client.StatusStream().ToPropertyEx(this, x =&gt; x.Status);
      }
  }
  
  public interface IStatus
  {
      string AoiStatus { get; }
  }
  </code></pre>
  
  <p>If I bind the gui via <code>xaml</code> with my <code>DataContext</code>, everything works as expected. <code>ViewModel.PropertyChanged</code> is fired, so I don't know what's wrong there?! </p>
  
  <pre class="lang-cs prettyprint-override"><code>public partial class MainWindow : ReactiveWindow&lt;AppViewModel&gt;
  {
      public MainWindow()
      {
          InitializeComponent();
          ViewModel = App.Container.GetInstance&lt;AppViewModel&gt;();
          DataContext = this;
      }
  }
  
  public class AppViewModel : ReactiveObject
  {
  
      public IStatus Status { [ObservableAsProperty] get; }
  
      public MyClient Client { get; }
  
      public AppViewModel(MyClient client)
      {
          Client = client;
          Client.StatusStream().ToPropertyEx(this, x =&gt; x.Status);
      }
  }
  
  public interface IStatus
  {
      string AoiStatus { get; }
  }
  </code></pre>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;TextBlock&gt;
      &lt;Run Text="Status:" /&gt;
      &lt;Run Text="{Binding ViewModel.Status.AoiStatus, Mode=OneWay}"/&gt;
  &lt;/TextBlock&gt;
  </code></pre>