openproject/app/views/issues/_subissues_paragraph.rhtml

<strong><%= l(:label_issue_hierarchy) %></strong>
(<%= link_to(l(:label_add_subtask), {:controller => 'issues', :action => 'new', :project_id => @project, :issue => {:parent_issue_id => @issue}}) if User.current.allowed_to?(:manage_subtasks, @project) %>)

<% indent = 0 %>

<form action="#">
  <table id="issue_tree" class="list">

    <!-- render parent elements -->
    <% @issue.ancestors.each do |issue| %>
      <%= render :partial => 'subissue_row', :locals => { :issue => issue, :level => indent, :relation => "parent" } %>
      <% indent += 1 %>
    <% end %>

    <!-- render current element -->
    <%= render :partial => 'subissue_row', :locals => { :issue => @issue, :level => indent, :relation => "root" } %>
    <% indent += 1 %>

    <!-- render child elements -->
    <% issue_list(@issue.descendants.sort_by(&:lft)) do |issue, level| %>
      <%= render :partial => 'subissue_row', :locals => { :issue => issue, :level => indent + level, :relation => "child" } %>
    <% end %>

  </table>
</form>