When trying to create a CustomLayout for Microsoft Unified Service Desk (USD) 3.0 I get the error:

Error 1 

> 
> Cannot create an instance of "PanelLayoutBase". c:\Visual Studio
>  2013\Projects\LayoutSolution\MyPanelLayout\CustomLayout.xaml 1 10 MyPanelLayout
> 
> 
> 

I am using Visual Studio 2013
Latest version of the SDK