WPF requires an extra property

source/SkiaSharp.Views/SkiaSharp.Views.WPF/SkiaSharp.Views.WPF.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <TargetFramework>net45</TargetFramework>
     <OutputTypeEx>library</OutputTypeEx>
+    <ExtrasEnableWpfProjectSetup>true</ExtrasEnableWpfProjectSetup>
     <RootNamespace>SkiaSharp.Views.WPF</RootNamespace>
     <AssemblyName>SkiaSharp.Views.WPF</AssemblyName>
     <PackagingGroup>SkiaSharp.Views</PackagingGroup>