title: Design DataContext not working as expected
body: <p>In a new WP8.1 project I create a ViewModel and use it for design data. My binding does not show the value I expect:</p>
  
  <pre><code>namespace App1
  {
      public class ViewModel
      {
          public ViewModel()
          {
              this.Name = "hello world";
          }
  
          public string Name
          {
              get; set;
  
          }
      }
  }
  
  &lt;Page
      x:Class="App1.MainPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:local="using:App1"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      mc:Ignorable="d"
      d:DataContext="{d:DesignInstance local:ViewModel}"&gt;
  
      &lt;Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"&gt;
          &lt;TextBlock Text="{Binding Name}" /&gt;
      &lt;/Grid&gt;
  &lt;/Page&gt;
  </code></pre>
  
  <p>In the design surface in Blend or the designer in Visual Studio I see the text "Name" instead of "hello world".</p>
  
  <p>The design-time DataContext of Page should be an instance of my ViewModel and {Binding Name} should be the value of the Name property of my inherited DataContext. What am I missing here?</p>