title: Django admin list_filter - dropdown widget
body: <p>I can change <code>list_filter</code> of related object to dropdown. The problem is when I want to filter on related objects of related object:</p>
  
  <pre><code>class Match(Model):
      team = models.ForeignKey('Team'...)
      away_team = ... (doesn't matter)
  
  class Team(Model):
      country = models.ForeignKey('Country'...)
  </code></pre>
  
  <p>When I want to filter <code>Match</code> objects by <code>Team</code>, I do:</p>
  
  <pre><code>list_filter = ['team__country']
  </code></pre>
  
  <p>To <code>dropdown</code> this filter, I use <a href="https://github.com/mrts/django-admin-list-filter-dropdown" rel="nofollow noreferrer">https://github.com/mrts/django-admin-list-filter-dropdown</a>:</p>
  
  <pre><code> list_filter[('team',RelatedDropdownFilter)]
  </code></pre>
  
  <p>When I want to filter <code>Match</code> objects by <code>Country</code> of their <code>Team</code>:</p>
  
  <pre><code>list_filter = ['team__country']
  </code></pre>
  
  <p>But when I want to make dropdown from this filter, it doesn't work:</p>
  
  <pre><code>list_filter = [('team__country',RelatedDropdownFilter)]
  </code></pre>
  
  <p>It looks the same as there were not <code>RelatedDropdownFilter</code> specified.</p>
  
  <p><strong>RelatedDropdownFilter</strong></p>
  
  <pre><code>class RelatedDropdownFilter(RelatedFieldListFilter):
      template = 'django_admin_listfilter_dropdown/dropdown_filter.html'
  </code></pre>
  
  <p><strong>Template</strong></p>
  
  <pre><code>{% load i18n %}
  &lt;script type="text/javascript"&gt;var go_from_select = function(opt) { window.location = window.location.pathname + opt };&lt;/script&gt;
  &lt;h3&gt;{% blocktrans with title as filter_title %} By {{ filter_title }} {% endblocktrans %}&lt;/h3&gt;
  &lt;ul class="admin-filter-{{ title|cut:' ' }}"&gt;
  {% if choices|slice:"4:" %}
      &lt;li&gt;
      &lt;select style="width: 95%;"
          onchange="go_from_select(this.options[this.selectedIndex].value)"&gt;
      {% for choice in choices %}
          &lt;option{% if choice.selected %} selected="selected"{% endif %}
           value="{{ choice.query_string|iriencode }}"&gt;{{ choice.display }}&lt;/option&gt;
      {% endfor %}
      &lt;/select&gt;
      &lt;/li&gt;
  {% else %}
  
      {% for choice in choices %}
              &lt;li{% if choice.selected %} class="selected"{% endif %}&gt;
              &lt;a href="{{ choice.query_string|iriencode }}"&gt;{{ choice.display }}&lt;/a&gt;&lt;/li&gt;
      {% endfor %}
  
  {% endif %}
  &lt;/ul&gt;
  </code></pre>
  
  <p>Do you know what should I do?</p>