         inst.$el.detach()
         $parent.prepend inst.$el
 
-    inst.$el.attr 'class', "messenger #{ opts.extraClasses }"
+    if inst._addedClasses?
+        inst.$el.removeClass inst._addedClasses
+
+    inst.$el.addClass classes = "#{ inst.className } #{ opts.extraClasses }"
+    inst._addedClasses = classes
 
     return inst


        parentLocations: ['body']

    opts = $.extend defaultOpts, opts

    locations = opts.parentLocations
    $parent = null

        msg = m_opts.messageInstance ? @newMessage m_opts

        if m_opts.id?
            msg.options.id = m_opts.id

        if m_opts.progressMessage?
            msg.update $.extend {}, m_opts,
