Peacecraft
Are you referring to this?
Neverfire7 Why can’t I edit my forum posts?
If someone has posted after your post, on the same thread, you will no long be able to delete or edit your post. This is probably to ensure that every conversation makes sense, instead of people editing their messages to make everyone else look strange. If you double post, then delete the second post, you will still not be able edit your post. The same applies with making a thread. If someone says something on it, even if it is later deleted, you will no longer be able to delete it or change the title.