mickeyboy
FB login
There are 2 kind of FB login
Method A. "Action:Login by facebook", it will pop-up a facebook login window (not redirection)
Method B. "Action:Login by facebook SDK".
1. login by other plugin ( for example, official FB plugin ),
2. then call "Action:Login by facebook SDK", it will use access token to login.
Multiple login
In dashboard, "User" tab -> "Login" -> "Enable Multiple Logins" and set property. (I have not tested them yet.)
If this solution does not work yet, there has another workaround, although it is a good solution.