title: IOS Facebook SDK : what wrong with sharerDidCancel:(id<FBSDKSharing>)sharer delegate?
body: <p>I use facebook sdk worked well except for delegate "<strong>sharerDidCancel:(id)sharer</strong>". </p>
  
  <p>When i cancel my share with native dialog FB app, the delegate "<strong>sharer:(id)sharer didCompleteWithResults:(NSDictionary *)results</strong>"  always called ? So i can't handle my users when they post or cancel the dialog share, is this a bug  of Facebook SDK for IOS ?</p>
  
  <p>Thanks for any helping!</p>