Creating and using .NET Core class library in ASP.NET project

I started a new ASP.NET Core WebApi project from Visual Studio. Project initialized and started without problem.

Now I want to add a .NET Core class library to contain logic separated from the app. So I right-clicked the src folder, chose Add -> New Project and chose Class LOibrary (.NET Core).

In my class library I created a new middleware:

namespace MyClassLib
{
    public class MyMiddleware
    {
        private readonly RequestDelegate _next;

        public MyMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            await _next.Invoke(context);
        }
    }
}

And created extension method for it:

namespace MyClassLib
{
    public static class MyMiddlewareExtensions
    {
        public static IApplicationBuilder UseMyMiddleware(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<MyMiddleware>();
        }
    }
}

So far nothing fancy.

In my web API I added a reference to that project:

"dependencies": {
    "Microsoft.NETCore.App": {
        "version": "1.0.0",
        "type": "platform"
    },
    "Microsoft.ApplicationInsights.AspNetCore": "1.0.0",
    "Microsoft.AspNetCore.Mvc": "1.0.0",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.0.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.0.0",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.0.0",
    "Microsoft.Extensions.Configuration.FileExtensions": "1.0.0",
    "Microsoft.Extensions.Configuration.Json": "1.0.0",
    "Microsoft.Extensions.Logging": "1.0.0",
    "Microsoft.Extensions.Logging.Console": "1.0.0",
    "Microsoft.Extensions.Logging.Debug": "1.0.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.0.0",
    "MyClassLib": "1.0.0-*"
}

But when I try to use my new class library in my WebApi startup class it doesn't seem to recognize it - showing the using MyClassLib in red (error) and not allowing me to use any of the classes inside it.

What am I missing here? previous to .NET Core this is something I used to do all the time...

EDIT

Strange, but if I disable ReSharper than everything works. If I re-enable ReSharper than it shows errors again but still compiles. I've seen posts on GitHub from people who encountered this problem on RC1 - but it was mentioned that it was fixed. Anyone knows how I can continue working with ReSharper and .NET Core?