fix.js

Drupal.chatroom.addPreviousMessageToBoard = function(message) {
  // Check for multiple chat windows
  if ($.isArray(Drupal.settings.chatroom.chats)) {
    for (var key in Drupal.settings.chatroom.chats) {
      if (Drupal.settings.chatroom.chats[key].cid === message.cid) {
        var chat = Drupal.settings.chatroom.chats[key];
      }
    }
  }
  else {
    var chat = Drupal.settings.chatroom.chats[message.cid];
  }
  console.log(Drupal.settings.chatroom.chats);
  chat.prevMsgId = message.cmid;
  Drupal.settings.chatroom.chats[message.cid] = chat;
  $('#chatroom-board-' + message.cid).prepend(message.msg);
}