I made a downvote and a suggestion to https://stackoverflow.com/a/11505552/974555 . Subsequently I tried undoing my downvote, but I get the message "You last voted on this answer 19 minutes ago, it is now locked unless the question is edited.". Here:

Can't undo my vote, even after the answer I voted on was editing

it is said that this behaviour won't change, and it is also said that I can't cancel because he was too quick in improving. My question is why. Why can't I undo a downvote upon the user improving based on my suggestion? Why is this not going to change?

  • The answer is given in the exact question you link to. The edit was apparently made within the grace period. So for the system there really is no edit. And as such you cannot change your vote. Nothing had changed after all (well, to the system that is). – Bart Jul 16 '12 at 14:14
  • possible duplicate of Can't undo my vote, even after the answer I voted on was editing – Bart Jul 16 '12 at 14:14
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    My question is not that it's technically impossible, but why the design is as it is. – gerrit Jul 16 '12 at 14:15
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    I just clicked on a downvote by mistake. Then I noticed that I did so 2h later (after lunch). The answer was usefull to me. It is a shame that I cannot undo it. The user lost points for this answer instead of getting my upvote. – gfrigon Mar 14 '16 at 18:41
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    There is more chance of accidentally clicking on a downvote on a tablet, because a scroll gesture may have registered as a click, if your finger was near the downvote button. Which I what I think happened to me, and I did not notice until the next morning. – Sanj Nov 24 '16 at 7:55
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    Because of this I cannot remove an accidental down vote from a perfectly good answer. stackoverflow.com/questions/45542103/… What should I do? – dbalakirev Oct 20 '17 at 10:43

Why can't I undo a downvote upon the user improving based on my suggestion?

When you try to undo your vote, the following process checks if you're able to:

  • When did you vote?

    If it was less than 5 minutes ago, allow.

  • When was the post edited for the last time?

    If it was after your vote, allow.

  • Deny.

Now, if the post gets edited after you voted but before the grace period expired, the edit won't make it into the revision history. But that's where When was the post edited for the last time? gets its answer from.

Why is this not going to change?

Changing this behavior would require edits in the grace period to be logged separately, just to allow undoing votes. Much work, little reward.


Posting a comment ends the grace period now, i.e., if a post gets edited after it received a comment, it will always create a new revision in the history.

Therefore, if you comment before casting a downvote, you'll be able to reverse it if/when the post gets fixed.

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    Is there any reason people are not allowed to undo their votes after the grace period ? – BlueTrin Aug 7 '12 at 8:48
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    For example, it makes strategic downvoting less attractive. 1. Post an answer. 2. Downvotes all other answers. 3. You're answer rises to the top, increasing the change of getting upvoted and/or accepted. 4. Once it did, undo all downvotes to recollect lost reputation. With the current restriction, this is impossible. – Dennis Aug 7 '12 at 11:16
  • @Dennis well, close to impossible. This can still be achieved through very nefarious means but someone has to be really hard-up for rep to do so. – Aaron Bertrand Sep 6 '12 at 13:54
  • @AaronBertrand: Yes, it is possible, but exploiting a bug to increase your reputation is certainly ban worthy. – Dennis Sep 6 '12 at 14:12
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    @Dennis yes, I tried to make that clear in my comment. I was just correcting the impossible statement. – Aaron Bertrand Sep 6 '12 at 14:13
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    I wish you were also allowed to undo a downvote when the original post author posts a clarifying comment. – bigblind Jan 6 '15 at 11:05
  • @bigblind That would be exploitable, too. To paraphrase Dennis: 1. Post an answer. 2. Downvote all other answers. 3. Your answer rises to the top, increasing the chance of getting upvoted and/or accepted. 4. Once it does, goad the answerers you downvoted into a fight/reply by commenting on their answers. 5. Once they reply, undo downvote to recollect lost reputation. (6. Get banned once they figure out what you're doing) – Braden Best Jun 12 '17 at 21:59

This is exactly why my typical practice is usually, if I see an answer within the grace period that needs improvement, I comment first, giving the user ample time to improve their post before I down-vote. If they don't improve it, or they argue about it, then I click. I always wait until the grace period is over so that, should they later decide to improve the post, I know I'll be able to reverse my down-vote. I try to also be good about removing my comments at the same time, if they are no longer relevant.

  • Good idea. I never knew about the grace period thing, but now that I do, I'll wait to downvote. – Antimony Apr 7 '13 at 5:39

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