       Messages.update
         root: child
       ,
-        $set: root: root ? child  ## actually must be root
+        $set: update  # root: root ? child  ## actually must be root
       ,
         multi: true
       EmojiMessages.update
         root: child
       ,
-        $set: root: root ? child  ## actually must be root
+        $set: update  # root: root ? child  ## actually must be root
       ,
         multi: true
       _noLongerRoot child if root?

  if parent?
    _messageAddChild child, parent, position
  if root != cmsg.root
    Messages.update child,
      $set: root: root
    EmojiMessages.update
      message: child
    ,
      $set: root: root
    ,
      multi: true
    if cmsg.root?

  message.updators = authors
  diff = _.clone message
  for author in authors
    message["authors.#{escapeUser author}"] = now
  Messages.update id,
    $set: message
  diff.id = id
