C# Definition:

// Windows Ribbon ContextualUI interface
[ComImport]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("EEA11F37-7C46-437c-8E55-B52122B29293")]
public interface IUIContextualUI
{
     // Sets the desired anchor point where ContextualUI should be displayed.
     // Typically this is the mouse location at the time of right click.
     // x and y are in virtual screen coordinates.
     [PreserveSig]
     HRESULT ShowAtLocation(Int32 x, Int32 y);
}

Notes:

None.