Logout doesn't work

[silvio-terzi]

The logout method doesn't really disconnect the user from Facebook. After logout, when I try to login again immediately, it doesn't open the login mask; instead open a page that said that you've just authorized the app (sometimes, or doesn't open a page at all), for the user just disconnected. If I want to change the user, I can't.
To login I've used the WebView only option.

[brainoffline]

This is a solution for WinRT

            // Clear out any facebook cookies
            var myFilter = new Windows.Web.Http.Filters.HttpBaseProtocolFilter();
            var cookieManager = myFilter.CookieManager;
            var myCookieJar = cookieManager.GetCookies(new Uri("https://facebook.com"));
            foreach (var cookie in myCookieJar)
                cookieManager.DeleteCookie(cookie);