Reading other threads I decided to try combining the two projects in one solution to see if that would aid debugging. Unfortunately when I try to add a Reference to the WindowsBase code, I get...
Incompatible Target Framework: .NETFramework, Version=v3.5
I tried changing it, it builds all the way back to 2.0, but none of these allowed the library to import. Note, this is not a PCL.
I am running the latest version of Xamarin on the Mac, 8.something, which downloaded yesterday.