title: What does a DesignNavigationService do? (related to MVVM Light toolkit)
body: <p>In the special Window 8 edition of MSDN Magazine (<a href="http://msdn.microsoft.com/en-us/magazine//jj651572.aspx" rel="nofollow">http://msdn.microsoft.com/en-us/magazine//jj651572.aspx</a>), Laurent describes initialize his SimpleIoc container, and also describes how to implement navigation from the ViewModels using a <code>NavigationService</code>, which implements <code>INavigationService</code>.</p>
  
  <p>However, in Figure 6, (which he says illustrates how to register the service), his code snippet clearly refers to a <em>design-time</em> NavigationService, named <code>DesignNavigationService</code>, which I presume is to support "Blendability" (Laurent is very big on supporting Blend, and I appreciate that).</p>
  
  <p>Does anyone know what is different about a design-time navigation service? There's no other mention of it in the article, and a few Bing searches turned up nothing useful.</p>