tracks/app/views/contexts/_mobile_context.rhtml

<%
# select actions from this context
@not_done = @not_done_todos.select {|t| t.context_id == mobile_context.id }

if not @not_done.empty? 
  # only show a context when there are actions in it
  -%>
<h2><%=mobile_context.name%></h2>
<ul class="c">
<%= render :partial => "todos/mobile_todo", 
           :collection => @not_done, 
           :locals => { :parent_container_type => "context" }-%>
</ul>
<% end -%>