When a student is making a post to a forum, if they double-click on the "Post to Forum" button, two posts will occur.
At first, I thought that this is really just a user problem... don't double-click! But then I got to wondering if there is a way in either php, or in other moodle code, to catch and ignore the second click? Then, I got to thinking about where else in Moodle a double-click might be a problem. Hmmm, maybe in other places where a form is filled out, such as filling out a profile and clicking Done. Somehow, as in this example, two student profiles are not created... no problem.
I do know that right now, according to Martin, that a lot of emphasis is being placed on improving forums, so maybe this request can be added to the list, if it is not already there.
Some discussion about this has occurred on moodle.org (https://moodle.org/mod/forum/discuss.php?d=236850).
I am using 2.5.1, and the problem is there. I think that this problem could have been around for awhile.