Normally the user would enter text and hit [Enter]. With current placement the user may need to enter the text, then click the provider button, and click [Sign in]. If we put the provider button in front of the whole box, then then prior to entering the id user would choose the provider (it also should be smartly preselected, e.g. from a cookie).

There fore instead of the sequence:

  • Enter text
  • Click, Click - to choose the provider (optional)
  • Click (or [Enter]) - to sign in

We'd have:

  • Click, Click - to choose the provider (optional)
  • Enter text
  • [Enter] (or Click) - to sign in

The second behavior looks faster and more natural.