WCF fully qualified type gotcha

It got me again, so I'm blogging it in the hope that I remember next time! When specifying fully qualified type names in .NET configuration files make sure to put a space after the comma that separates the parts(highlighted in yellow below).

   
<extensions>
 <behaviorExtensions>
       <add name="federatedServiceHostConfiguration" type="Microsoft.IdentityModel.Configuration.ConfigureServiceHostBehaviorExtensionElement, Microsoft.IdentityModel, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>
     </behaviorExtensions>
   </extensions>
</pre></code>