You have some authentication types. This addon assumes you have completed authentication setup, which is implemented in concrete5 core, see here for more info.
In dashboard/system/registration/authentication, the admin of concrete5 can choose the order of authentcation for login, but it is a site-wide setting. When the admin sets the order, the order is applied to all logins.
his addon does;
Suppose a case where Alice prefers Facebook and Bob prefers Google.
The admin sets the order of login authentication type. If the admin sets Facebook as default, Alice will be happy, but Bob not. If the admin sets Google as default, Bob will be happy, but Alice not.
This addon improves user interface.
Alice clicks Facebook login buttun. Next time, she will be displayed Facebook login as default. Bob clicks Google login button. Next time, he will be displayed Google login as default. Hence, both Alice and Bob will be happy.
*Notice* This addon uses a local storage. Browsers which supports HTML5 assumed.
This addon is not a tutorial or support for concrete5 core's authentication type setting. Be sure to setup API before purchasing this addon.