For an app on Windows Phone, I'm missing the page after you enter your login credentials and click submit. When I debug on my device, after I log in I obtain the correct response Uri with access token. But it ends there. It does not ask if I want to give the app permissions or not.
It is supposed to show what username you are logged in as and also provide two buttons to either accept or deny the application access. (see image below)
I'm following the same login procedure as Facebook client.