title: Exception while XamlReader.Load(..)
body: <p>i get an Exception during (UIElement)XamlReader.Load(...) which says </p>
  
  <pre><code>'Cannot create unknown type 'TextBox'.' Line number '1' and line position '2'.
  </code></pre>
  
  <p>on the following xaml:</p>
  
  <pre><code>&lt;TextBox Name="inputMyFirstString" BorderThickness="0" HorizontalAlignment="Stretch" Text="test"&gt;&lt;/TextBox&gt;
  </code></pre>
  
  <p>What did i wrong?</p>