title: How to use the x:SynchronousMode attribute
body: <p>I want to load a loose xaml file at runtime asynchronously. I read in the msdn documentation that the xaml reader therefore requires the attribute 'x:SynchronousMode="Async"' on the root element of the xaml file. If I define this attribute on the root element, Visual Studio 2012 tells me, that this attribute is not contained in the XAML namespace. Because of this, the designer window, which displays the visual representation of my xaml file, doesn't show anything except "Invalid Markup".</p>
  
  <p>Here are the first lines of my loose xaml file:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8" ?&gt;
  &lt;DockPanel xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         x:SynchronousMode="Async" LastChildFill="True"&gt;
  </code></pre>
  
  <p>What is the problem?</p>
  
  <p>Greetings,
  Kevin</p>