redmine/app/views/issues/_subtasks.html.erb

<div class="contextual">
  <%= link_to_new_subtask(@issue) if User.current.allowed_to?(:manage_subtasks, @project) %>
</div>

<p>
  <strong><%=l(:label_subtask_plural)%></strong>
  <%= render_descendants_stats(@issue) unless @issue.leaf? %>
</p>

<%= form_tag({}, :data => {:cm_url => issues_context_menu_path}) do %>
  <%= render_descendants_tree(@issue) unless @issue.leaf? %>
<% end %>