efcore: DataAnnotations not working in UWP at design-time

I created the following minimal example, a new project in VS2015.3 on win10 with added dependencies and the App.Config like described in the tutorial. I called the project SQLMinimalTest. The following code is the only code I added to a fresh UWP template.

using Microsoft.EntityFrameworkCore;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Windows.UI.Xaml.Media;

namespace SQLMinimalTest
{
public class Blog
{
    [Key]
    public int BlogID { get; set; }
    public string RandomString { get; set; }

    [NotMapped]
    public SolidColorBrush Brush
    {
        get { return _Brush; }
        set { _Brush = value; }
    }
    [NotMapped]
    private SolidColorBrush _Brush;
}

public class BloggingContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlite("Filename=BloggingTest.db");
    }
}
}

When I now type Add-Migration mig1 -Verbose in Package Manager Console, I get the following Error:

PM> Add-Migration mig1 -Verbose
Using startup project 'SQLMinimalTest'.
Using project 'SQLMinimalTest'
Build started...
Build succeeded.
Using application base 'D:\Programmieren\C#\VS2015 Testprojects\SQLMinimalTest\SQLMinimalTest\bin\x86\Debug\'.
Using application configuration 'D:\Programmieren\C#\VS2015 Testprojects\SQLMinimalTest\SQLMinimalTest\App.Config'
Using current directory 'D:\Programmieren\C#\VS2015 Testprojects\SQLMinimalTest\SQLMinimalTest\bin\x86\Debug\'.
Finding DbContext classes...
Using context 'BloggingContext'.
System.InvalidOperationException: The key {'TempId'} contains properties in shadow state and is referenced by a relationship from 'SolidColorBrush' to 'Blog.Brush'. Configure a non-shadow principal key for this relationship.
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.KeyConvention.Apply(InternalModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Conventions.Internal.ConventionDispatcher.OnModelBuilt(InternalModelBuilder modelBuilder)
   at Microsoft.EntityFrameworkCore.Metadata.Internal.Model.Validate()
   at Microsoft.EntityFrameworkCore.Metadata.Internal.InternalModelBuilder.Validate()
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.CreateModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.<>c__DisplayClass14_0.<GetModel>b__0(Object k)
   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)
   at Microsoft.EntityFrameworkCore.Infrastructure.ModelSource.GetModel(DbContext context, IConventionSetBuilder conventionSetBuilder, IModelValidator validator)
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.CreateModel()
   at Microsoft.EntityFrameworkCore.Internal.LazyRef`1.get_Value()
   at Microsoft.EntityFrameworkCore.Internal.DbContextServices.get_Model()
   at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServiceCollectionExtensions.<>c.<AddEntityFramework>b__0_4(IServiceProvider p)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.FactoryService.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.ScopedCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass12_0.<RealizeService>b__0(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetService[T](IServiceProvider provider)
   at Microsoft.EntityFrameworkCore.Design.Internal.DesignTimeServicesBuilder.<>c__DisplayClass7_0.<ConfigureContextServices>b__9(IServiceProvider _)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.FactoryService.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.TransientCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ConstructorCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.TransientCallSite.Invoke(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass12_0.<RealizeService>b__0(ServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
   at Microsoft.EntityFrameworkCore.Design.MigrationsOperations.AddMigration(String name, String outputDir, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_1.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
The key {'TempId'} contains properties in shadow state and is referenced by a relationship from 'SolidColorBrush' to 'Blog.Brush'. Configure a non-shadow principal key for this relationship.

and the project.json:

{
  "dependencies": {
    "Microsoft.EntityFrameworkCore.Sqlite": "1.0.0",
    "Microsoft.EntityFrameworkCore.Tools": "1.0.0-preview2-final",
    "Microsoft.NETCore.UniversalWindowsPlatform": "5.2.0"
  },
  "frameworks": {
    "uap10.0": {}
  },
  "runtimes": {
    "win10-arm": {},
    "win10-arm-aot": {},
    "win10-x86": {},
    "win10-x86-aot": {},
    "win10-x64": {},
    "win10-x64-aot": {}
  }
}

This is not the expected outcome. With the previous version I did not have this issue.