Hi,
I would like to note that the login operation, performed by different contexts to your services, it should have a homogeneous interface.
In particular, the captcha control should be the last element required to the person before the login prompt.
The management console provides authentication to a different location for the check stays connected, which should appear immediately instead after the textbox for the password (as run by login to the community)
Also use the same font (name, size and style) helps to recognize how unique your authentication system.
Regards
Web - popup OAuth
Web - Management console
Web - Community