Preventing automatic sign-in when using Google+ Sign-In

Question

I am in the process of integrating Google+ sign in with my site, which also lets users sign in with Twitter and Facebook. The sign in page of the site therefore has 3 button

Answer 1

Just check for g-auth-window in the callback function:

    function google_sign_callback(authResult){
        if(authResult['g-oauth-window']){

        }else if(authResult['error']) {

        }
    }