When you want to answer someone's comment but fail the captcha thing (the anti-spam) (aka you missread the letters and type something wrong):
1) You are notified of your failure (as expected)
2) The form is already filled with your not-yet-send message, you just have to try again this damn captcha (that's cool)
3) But it's not longer linked to the comment you originally wanted to answer :/
You may have noticed that the form isn't anymore where it was before (just below the comment you wanted to answer and not below all the thread), but you think this may be normal, that maybe this would have been difficult to display it the right place, so you think "it's ok".
UNTIL!!! you managed to pass the captcha thing and realize that you actually answered to the void, that you are talking to yourself. This darn form posted your comment down below the thread. And it's not linked with the comment you wanted to answer at all. What an akward situation.
PS: I don't think it's due to a specific OS, nor a browser (but I might be wrong). I don't know the dokuwiki version (I can't find it anywhere) but I experimented this trouble more than once on this wiki ( http://sebsauvage.net/wiki/doku.php?id=php:zerobin_discussion
) maybe some of you will know how to get the version out of it. Have a good day! (That's my first bug report in my life, be kind!)