Why should your visitors already be connected to Facebook to get their promo code?
When a client clicks the module "Like" button to get his promo code, he may not already be logged in to Facebook.
But in this case, it's the Facebook authentication plugin that takes over in a popup to log in to Facebook. Unfortunately, once the client is logged in, this plugin does not trigger the execution of the callback script linked to the "click" action on the "like" button. Therefore, our script is not executed and the fancy box offering the coupon code does not appear... To get the promo code, the customer must reload the page and click again the "Like" button.
This is because the Facebook cookie that detects if a person is logged in or not to Facebook, isn't updated in the main window but only in the popup that has just opened. This is due to the Facebook working and we cannot technically overcome this problem.