Why do I have two different permission get dialogues in Facebook API?

Question

I have two sites in my Apps account and I\'ve got them working for Facebook OAuth, why almost same FB login buttons lead to different permissions asking page.

First, not

Answer 1

It seems that the first one has enabled the new auth dialog

Check your app settings. For more information, please refer to this doc: https://developers.facebook.com/docs/beta/authentication/