anchor.diff:                      controller: 'submissions',
                       action: 'browse',
                       id: @assignment.id %>
  +      </li>
  +      <li <% if controller.controller_name == 'summaries' %>
  +            class='active'
  +          <% end %>>
  +        <%= link_to t(:summaries),
  +                    assignment_summaries_path(@assignment) %>
         </li>
       <% end %>
     </ul>
  
positive.code:       </span>
      </li>
      <% if controller.controller_name == 'submissions' ||
            controller.controller_name == 'results' %>
        <li <% if controller.controller_name == 'submissions' ||
                  controller.controller_name == 'results' %>
              class='active'
  
negative.code:   <% end %>
  <% elsif @current_user.ta? && (controller.controller_name == 'assignments' ||
                                  controller.controller_name == 'submissions' ||
                                  controller.controller_name == 'results' ||
                                  controller.controller_name == 'summaries') %>
    <ul class='sub'>
      <li id='dropdown'>
        <span class='dropdown'>
  