anchor.diff:  <%= render :partial => '/sign_up_sheet/add_topics' %>
   
   <% if @assignment.staggered_deadline == true %>
  -    <a href="#image" onClick="toggleVis('image');">
  -    <span class="inline" id="image_show">Show dependency graph</span>
  -    <span class="inline" id="image_hide" style="display: none">Hide dependency graph</span>
  -  </a>
  -
  -  <div id="image_myDiv" style="display:none" align="center">
  -    <img src='/assets/staggered_deadline_assignment_graph/graph_<%= @assignment.id %>.jpg'/>
  -  </div>
   
     | <a href="#due_date" onClick="toggleVis('due_date');">
       <span class="inline" id="due_date_show">Show start/due date</span>
  
positive.code:       <% for topic in @sign_up_topics %>
          <tr>
            <%= render :partial => '/sign_up_sheet/table_line', :locals => {:i=>i, :topic=>topic} %>
            <td align="center">
              <% topic_identifier = SignUpTopic.where(assignment_id: @assignment.id).map {|u| [u.topic_identifier, u.id] } %>
              <% topic_identifier.delete([topic.topic_identifier, topic.id]) %>
              <% select = TopicDependency.find_by_topic_id(topic.id)%>
              <% selected = Array.new%>
              <% if !select.nil?
                   selected = select[:dependent_on].to_a
              end%>
              <%= select_tag 'topic_dependencies_' + topic.id.to_s + '[dependent_on][]', options_for_select( topic_identifier, selected), :multiple => true, :size => 2 %>
            </td>
  
          </tr>
          <% i=i+1 %>
        <% end %>
  
negative.code:   <% end %>
  
  <% end %>
  