Can't add user to a role

I follow the MS guidelines and they give a specific example as follows.

ALTER ROLE Sales ADD MEMBER Barry;

However, when I perform corresponding operation, I get an error telling me that "Incorrect syntax near the keyword 'ADD'" and a line under the keyword ADD. When I hover over it, I can see that the tooltip says "Expecting WITH".

As far I can see, WITH is used for other alternation that addition of users to roles. So my question is twofold.

1. What can I do to add the user to the role?
2. What's upp with the misguided tooltip?

Somewhere else on the internet, I've seen that the users are added to roles by calling a stored procedure instead. That begs a question what the MSDN link is talking about - as if it's not possible to use that script. Suggestions are welcome on the subjects as I'm less than experienced with DBs and feel like a moose on the ice.

My config: Microsoft SQL Server Management Studio 10.50.4000.0
Microsoft Data Access Components (MDAC) 6.1.7601.17514
Microsoft MSXML 3.0 4.0 5.0 6.0
Microsoft Internet Explorer 9.0.8112.16421
Microsoft .NET Framework 2.0.50727.5466
Operating System 6.1.7601