Visual Studio 2017 release .NET Core 1.1.1 Razor Tag Helpers do not get colorization

Hi,

My .csproj contains 

<PackageReference Include="Microsoft.AspNetCore.Razor.Tools" Version="1.1.0-preview4-final" />

but Razor Tag Helpers do not get colorization nor intellisense.

Any help how to solve this problem please?

Thanks