VS2013 Designer will not load with OxyPlot control

I am attempting to use OxyPlot in my Windows Universal application. I have imported the OxyPlot Core and Universal Packages from NuGet, and Built a simple Application. It runs correctly. However the Visual Studio 2013 Update 4, Designer does not like me inserting a PlotView control. I am unable to design in PlotView control as I just get
"Could Not Find Windows Runtime type "Windows.UI.Xaml.Control.RelativeSource".

See Below