OxyPlot.Xamarin.Forms package breaks Resource.Designer.cs?

Note that there are 2 different project templates: Portable and Shared. In your post you mention both of them, so be clear about which one you're using. The specific example you're following is for a Portable project template. After adding the OxyPlot Nuget Package, I had to manually add OxyPlot and OxyPlot.Xamarin.Forms to the References of the Portable one. After that, it worked just fine. I'm using Xamarin.Forms 2.0.0.6482 and OxyPlot 1.0.0-unstable1983.

I added the PlotView using code:

App.cs:

 public App()
    {
        PlotModel plotModel = new PlotModel { PlotAreaBackground = OxyColors.LightYellow };
        plotModel.Series.Add(new FunctionSeries(Math.Sin, -10, 10, 0.1, "sin(x)"));

        // The root page of your application
        MainPage = new ContentPage {
            Content = new PlotView {
                VerticalOptions = LayoutOptions.Fill,
                HorizontalOptions = LayoutOptions.Fill,
                Model = plotModel
            }
        };
    }