I have an iPad app that was built in Adobe Air, the app currently requires that users register and login.
What I would like is for users to login with their Facebook account, but this would require a Facebook dialog to appear within my app, either with StageWebView or in a browser window.
The Spotify client on windows PC doesn’t show this dialog, instead you can enter your FB credentials into a normal text box:

This is how I would like my iPad app to behave, so I can keep my current login form.
I’m pretty sure this is the result of a special partnership between Facebook and Spotify. Generally, Facebook doesn’t want you collecting users’ passwords on your forms as a security precaution.