Redmine/app/views/watchers/_watchers.html.erb

<% if User.current.allowed_to?(:add_issue_watchers, @project) %>
<div class="contextual">
<%= link_to_remote l(:button_add),
                   :url => {:controller => 'watchers',
                            :action => 'new',
                            :object_type => watched.class.name.underscore,
                            :object_id => watched},
                   :method => 'get' %>
</div>
<% end %>

<h3><%= l(:label_issue_watchers) %> (<%= watched.watcher_users.size %>)</h3>

<%= watchers_list(watched) %>