Index: app/controllers/messages_controller.rb
===================================================================
--- app/controllers/messages_controller.rb	(revision 15400)
+++ app/controllers/messages_controller.rb	(working copy)
@@ -47,6 +47,7 @@
       limit(@reply_pages.per_page).
       offset(@reply_pages.offset).
       to_a
+    @replies.reverse! if User.current.wants_comments_in_reverse_order?
 
     @reply = Message.new(:subject => "RE: #{@message.subject}")
     render :action => "show", :layout => false if request.xhr?
Index: test/functional/messages_controller_test.rb
===================================================================
--- test/functional/messages_controller_test.rb	(revision 15400)
+++ test/functional/messages_controller_test.rb	(working copy)
@@ -71,6 +71,17 @@
     assert_select 'div#reply textarea#message_content'
   end
 
+  def test_show_comments_sorting_desc
+    user = User.find(2)
+    user.pref.comments_sorting = 'desc'
+    user.pref.save!
+    @request.session[:user_id] = user.id
+    get :show, :board_id => 1, :id => 1
+    assert_response :success
+    replies = assigns(:replies)
+    assert replies.first.created_on > replies.last.created_on
+  end
+
   def test_show_message_not_found
     get :show, :board_id => 1, :id => 99999
     assert_response 404