In this method We Will Make Invisible Hidden Page Manager For Security Purpose ( It's Not a Bug It's Just a working Trick ).
Steps To Hide Page Manager :-
1) First Make any New Email ( remember email should be fresh and shouldn't be attached with any Facebook Profile ). Recommended - Yahoo, Gmail etc
2) Then Go To Your Page Admin Roles :- and Add The Email and Save It as Manager of Your Page! The Email will be added Automatically But Not will be on Screen ( Just Hidden ).
3) Now Lets Suppose Your Page Got Hacked or Someone cheated you! You Completely Lost Your Page Admin Access What To do Now ??
4) Yes, Go to the Email there should be Email From Facebook About Your Invitation of That Page Which You added Accept It as Manager of Page, now Make New FB account with that Email and Go to Message there will be invitation open it and You are Now Manager! KICK the Scammer/Hacker/Cheater Out of Page and Add New Email Again For Security Reason Again Like this