diff --git a/app/controllers/attachments_controller.rb b/app/controllers/attachments_controller.rb
index db77283cc..d87bc6d2c 100644
--- a/app/controllers/attachments_controller.rb
+++ b/app/controllers/attachments_controller.rb
@@ -180,9 +180,10 @@ class AttachmentsController < ApplicationController
     end
 
     respond_to do |format|
-      # modify by nwb
       if !@attachment.container.nil? &&
-         (@attachment.container.is_a?(Course) || ((@attachment.container.has_attribute?(:course) ||@attachment.container.has_attribute?(:course_id) )  && @attachment.container.course ) || ((@attachment.container.has_attribute?(:board) || @attachment.container.has_attribute?(:board_id)) && @attachment.container.board && @attachment.container.board.course ) )
+         (@attachment.container.is_a?(Course) || ((@attachment.container.has_attribute?(:course) || @attachment.container.has_attribute?(:course_id) )  &&
+         @attachment.container.course ) || ((@attachment.container.has_attribute?(:board) || @attachment.container.has_attribute?(:board_id)) &&
+         @attachment.container.board && @attachment.container.board.course ) )
         if @attachment.container.is_a?(News)
           format.html { redirect_to_referer_or news_path(@attachment.container) }
         elsif @attachment.container.is_a?(Message)