title: PropertyChangedEventHandler not firing asynchronically
body: <p>I've implemented this property to hide and show an element:</p>
  
  <pre><code>private bool isWorking = false;
  
  public bool IsWorking {
      get {
          return this.isWorking;
      }
  
      set {
          this.isWorking = value;
          OnPropertyChanged("IsWorking");
      }
  }
  
  public event PropertyChangedEventHandler PropertyChanged;
  
  protected void OnPropertyChanged(string name)
  {
      PropertyChangedEventHandler handler = PropertyChanged;
      if (handler != null)
      {
          handler(this, new PropertyChangedEventArgs(name));
      }
  }
  </code></pre>
  
  <p>But when i change the property, even if the method is async, it's changing in a sync way.</p>
  
  <p>Can you explain me how to solve the issue? I tried to move a dispatcher event inside the property changed or the code, but it doesn't work!</p>