.NET 4.0 - Microsoft.Windows.Shell - where is it?

Question

I'm playing around with the examples for the Sofa V2.5, which is a WPF Docking framework.

These are VS2010, .NET 4.0. In one project, there's a reference to a "Microsoft.Windows.Shell" assembly, which is unresolved.

When I open the Add Reference and look for .NET assemblies, I don't see Microsoft.Windows.Shell. Why not? I'm running VS2010 on Windows 7. How can it be missing? If it's not missing, why can't VS2010 see it?

Answer 1

It has a NuGet package now:

Install-Package Microsoft.Windows.Shell

Update June 2020: Based on update provided by @yaron in the comments, this package is no longer available. As the NuGet page states:

The owner has unlisted this package. This could mean that the package is deprecated or shouldn't be used anymore.

Answer 2

It is probably included with this : Ribbon (WPF)