You must have opened a discussion thread instead of a question thread. Happened to me once on a different section of the forum, although I'm still not sure how I managed to do it. Well anyway, one of the moderators came and changed it, but I don't know if there is a way to do it yourself.
Ok. Thanks. This thread just have to do without a best answer then, and I will remember next time to open a discussion thread.
Thank you all to make me understand more ;-)