title: System.ArguementException while calling RenderAsync() in windows phone RT app
body: <pre><code>Grid TestGrid = new Grid();
  TestGrid.Background = new SolidColorBrush(Colors.AliceBlue);
  TestGrid.Height = 500;
  TestGrid.Width = 500;
  await bitmapRender.RenderAsync(TestGrid, 500, 500);
  </code></pre>
  
  <p>This code in its last statement gives me the following error:</p>
  
  <p><em>System.ArgumentException</em></p>
  
  <p><em>Value does not fall within the expected range.</em></p>
  
  <p>What's wrong in this apparently simple code?</p>
  
  <p><strong>Edit:</strong> Futher details on the bug:</p>
  
  <p>{System.ArgumentException: Value does not fall within the expected range.
     at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
     at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
     at Picture_Slide.MainPage.d__0.MoveNext()}</p>