Comment 4 for bug 1703109

I must add that, while quite rough around the edges, the browser blocking the request due to required fields being empty is correct in my opinion. A field being invisible does not simply mean it is no longer required.

As far as I can see, there are three possible fixes for this problem:
1) Wrap the user/pass/domain/region in an ng-if block
2) Kick out html's required and use ng-required
3) Toggle the required attribute when showing and hiding the element

While not the most beautiful of the three, I have implemented #3 as a two-liner and confirmed it works on Chrome, FF, IE and Edge (although I don't know if it was ever an issue on IE and Edge).
If joining as a developer is not too much work I'll create a review tomorrow, otherwise I might just add it here.