//this will work
    private void button1_Click(object sender, RoutedEventArgs e)
    {
        var query = ctx.AccountSet;
        query.BeginExecute((result) =>
        {
            textBox1.Text = query.EndExecute(result).First().Name;
        }, null);
    }

    //this will fail
    private void button2_Click(object sender, RoutedEventArgs e)
    {
        System.Threading.Tasks.Task.Factory.StartNew(RestAsync);
    }

    void RestAsync()
    {
        var query = ctx.AccountSet;
        var async = query.BeginExecute(null, null);
        var task = System.Threading.Tasks.Task.Factory.FromAsync<Account>(async, (result) =>
        {
            return query.EndExecute(result).First(); // <- Exception thrown here
        });
        textBox1.Dispatcher.BeginInvoke(() =>
        {
            textBox1.Text = task.Result.Name;
        });
    }

private static AsyncCallback SyncContextCallback(AsyncCallback callback)
{
  SynchronizationContext sc = SynchronizationContext.Current;
  // If there is no SC, just return what was passed in
  if (sc == null) return callback;
  // Return a delegate that, when invoked, posts to the captured SC a method that
  // calls the original AsyncCallback passing it the IAsyncResult argument
  return asyncResult => sc.Post(result => callback((IAsyncResult)result), asyncResult);
}

protected override void OnMouseClick(MouseEventArgs e) {
  // The GUI thread initiates the asynchronous Web request
  Text = "Web request initiated";
  var webRequest = WebRequest.Create("http://Wintellect.com/");
  webRequest.BeginGetResponse(SyncContextCallback(ProcessWebResponse), webRequest);
  base.OnMouseClick(e);
}

private void ProcessWebResponse(IAsyncResult result) {
  // If we get here, this must be the GUI thread, it's OK to update the UI
  var webRequest = (WebRequest)result.AsyncState;
  using (var webResponse = webRequest.EndGetResponse(result)) {
      Text = "Content length: " + webResponse.ContentLength;
  }
}

public override void UpdateCanvas(object parameter)
 {
      Action<GraphPane> startToUpdate = StartToUpdate;
       GraphPane selectedPane = Canvas.HostingPane.PaneList.Find(p =>  p.Title.Text.Equals(defaultPanTitle));
       startToUpdate.BeginInvoke(selectedPane, FormSyncContext.SyncContextCallback(RefreshCanvas), selectedPane);
 }

 public static AsyncCallback SyncContextCallback(AsyncCallback callback)
 {
       // Capture the calling thread's SynchronizationContext-derived object
       SynchronizationContext sc = SynchronizationContext.Current;

       // If there is no SC, just return what was passed in
       if (sc == null) return callback;

       // Return a delegate that, when invoked, posts to the captured SC a method that
       // calls the original AsyncCallback passing it the IAsyncResult argument
       return asyncResult => sc.Post(result => callback((IAsyncResult)result), asyncResult);
 }