Last night we switched over to a new Friend Inviter provided by Facebook as the old one we were using started to break on different browsers. We will be working on our own that should look very similar to the old version and provide a similar user interface, the current version still provides all the same filters as shown in the image below. We will see if there is anything we can do to make that clearer in-game while we work to get our own version out. If you have issues with the temporary solution please let us know as it will help us raise the priority on the development of a new friend inviter.
Just added a new button that should preload with friends already playing, those with a ton of friends seem to be having some issues with it. We have increased the priority of dev'ing our own version and hope to have something ready for early next week. Sorry for any inconvenience, the other one started to become buggy and was no longer being supported by Facebook.
The current invite systemed borrowed from Facebook when set to "Invite Friends Playing" or "Pirate Clan Players" will just go off and think about doing something, but never brings up anyone to invite. Please put the old system back in. Even if it had problems, at least it worked 99% of the time.
