When someone creates a new account on an SE site, and when he/she flags a post for the first time, he/she can't see whether this flag is still active, or got declined, because the "Helpful flags" link only appears when someone has at least one flag marked as helpful. This could be annoying, because if this flag gets rejected, then he/she can't see why this flag was rejected (if a specific reason is added).
So, my suggestion is: after someone has flagged one post (and if it's not yet marked as helpful), show a "Helpful flags: 0" link, so people can see whether his/her flag is still active or declined.