I use Xamarin.Forms for around 4 months now, and it is really great for me.
However, when I updated Visual Studio 2017 Enterprise on my laptop to the latest version (15.7) and open my exact same project that has no error whatsoever, I got errors in some object properties (including BackgroundColor, BorderColor, and FontSize). All of these has only one error, XLS0431. Although, I do not upgrade my project to Xamarin 3.0, yet (I still use Xamarin 18.104.22.1684934 with the PCL and .NET Standard 2.0).
I binged and googled, I cannot find solution for this error (maybe it quite new one) and I still figure out why it has this kind of problem. If you guys figure it out, feel free to live the comment here.