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

<div class="contextual">
<% if User.current.allowed_to?(:manage_issue_relations, @project) %>
  <%= toggle_link l(:button_add), 'new-relation-form', {:focus => 'relation_issue_to_id'} %>
<% end %>
</div>

<p><strong><%=l(:label_related_issues)%></strong></p>

<% if @relations.present? %>
<%= form_tag({}, :data => {:cm_url => issues_context_menu_path}) do %>
  <%= render_issue_relations(@issue, @relations) %>
<% end %>
<% end %>

<%= form_for @relation, {
                 :as => :relation, :remote => true,
                 :url => issue_relations_path(@issue),
                 :method => :post,
                 :html => {:id => 'new-relation-form', :style => 'display: none;'}
               } do |f| %>
<%= render :partial => 'issue_relations/form', :locals => {:f => f}%>
<% end %>