So I am updating an older desktop app (written in VB, .net 4.0) with facebook integration and followed the guide found [here](https://developers.facebook.com/docs/facebook-login/login-flow-for-web-no-jssdk/), and have been able to successfully get a token (by parsing the uri of the embedded webview if it contains "token="). Now my problem is if I try to login with a facebook account that has already approved the app in a prior session, the webview just gets redirected to <https://www.facebook.com/connect/login_success.html> without any token information. 

Do I HAVE to log all of the tokens I generate manually (ie on successful token generation, I can call their profile info, use their FB ID as key and save the token)? Even if I do, since the email and password is input directly into the facebook login window, how do I check if the user already has a token?

Thanks in advance