python - Django messages refuse to display -

i've been trying display alert whenever user posts invalid comment on site (such blank post). decided use messages framework, doesn't seem work. i've made sure app, middleware, , template context processors correct, , views using requestcontext object. if use {% debug %} in template, can see "messages" variable set, nothing in there.

settings.py

installed_apps = (     'django.contrib.admin',     'django.contrib.auth',     'django.contrib.contenttypes',     'django.contrib.sessions',     'django.contrib.messages',     'django.contrib.staticfiles',     'polls', )  middleware_classes = (     'django.contrib.sessions.middleware.sessionmiddleware',     'django.middleware.common.commonmiddleware',     'django.middleware.csrf.csrfviewmiddleware',     'django.contrib.auth.middleware.authenticationmiddleware',     'django.contrib.auth.middleware.sessionauthenticationmiddleware',     'django.contrib.messages.middleware.messagemiddleware',     'django.middleware.clickjacking.xframeoptionsmiddleware', )  template_context_processors =  ("django.contrib.auth.context_processors.auth",     "django.core.context_processors.debug",     "django.core.context_processors.i18n",     "django.core.context_processors.media",     "django.core.context_processors.static",     "django.core.context_processors.tz",     "django.core.context_processors.request",     "django.contrib.messages.context_processors.messages", ) 

views.py

def detail(request, question_id):     uid = request.session.get('uid', 0);     q = get_object_or_404(question, pk=question_id);      context = requestcontext(request, {'question': q, 'uid':uid});     return render(request, 'detail.html', context_instance=context);  def post_comment(request, question_id):     try:         if (request.post['comment_text'] == ""):             messages.error(request, "cannot submit empty comment!");             return httpresponseredirect(reverse('detail', kwargs={'question_id': question_id}));         else:             comment = comment(                 question = question.objects.get(id=question_id),                 submitter = request.session['uid'],                 text = sanitizer.clean(request.post['comment_text'])                 );              comment.save();      except exception, e:         raise e;     else:         return httpresponseredirect(reverse('detail', kwargs={'question_id': question_id})); 

detail.html

{% extends "base.html" %}  {% block content %} {% if messages %} <ul class="messages">     {% m in messages %}     <li{% if m.tags %} class="{{ m.tags }}"{% endif %}>{{ m }}</li>     {% endfor %} </ul> {% endif %} {%endblock%} 

by default, messages use storage.fallback.fallbackstorage storage backend, "first uses cookiestorage, , falls using sessionstorage messages not fit in single cookie". effectively, uses cookies storage backend. if there site may affecting that, can try setting use sessions specifically:

 message_storage = 'django.contrib.messages.storage.session.sessionstorage'