title: Django-cms CMS plugin with inlines once created inlines dont appear in Edit mode
body: <p>I have a widget 'quick links' I want to add in my footer (In a static placeholder)</p>
  
  <p>I can add the widget and all the inlines. Once created, I can see the inlines in published mode, but the widget is empty in edit mode. Can you help me please?</p>
  
  <p>Models.py</p>
  
  <pre><code>class LienFooterPlugin(CMSPlugin):
      langue = models.CharField(max_length=128)
  
  def copy_relations(self, oldinstance):
      self.lien_footer = oldinstance.lien_footer.all()
  
      for lien_footer in oldinstance.lien_footer.all():
          lien_footer.pk = None
          lien_footer.plugin = self
          lien_footer.save()
  
  class LienFooter(models.Model):
      class Meta:
          ordering = ["ordre"]
  
      lienfooter  = models.ForeignKey(LienFooterPlugin, related_name="lien_footer")
      titre   = models.CharField(max_length=150, blank=True, null=True)
      adresse     = models.CharField(max_length=150, blank=True, null=True)
      ordre       = models.PositiveIntegerField(default=1)
  </code></pre>
  
  <p>admin.py</p>
  
  <pre><code>class LienFooterInline(admin.StackedInline):
      model = LienFooter
  </code></pre>
  
  <p>cms_plugins.py</p>
  
  <pre><code>class LienFooterAppPlugin(CMSPluginBase):
      model = LienFooterPlugin
      name = u'Liens rapides'
      render_template = "widget/_liens_footer.html"
      inlines = (LienFooterInline,)
  
  
      def __init__(self, model=None, admin_site=None):
          super(LienFooterAppPlugin, self).__init__(model=model,
                                                    admin_site=admin_site)
          for inline in self.inlines:
              inline.placeholder = self.placeholder
              inline.page = self.page
  
  
      def render(self, context, instance, placeholder):
          context = super(LienFooterAppPlugin, self).render(context, instance, placeholder)
          items = instance.lien_footer.all()
          context.update({
              'model':instance,
              'placeholder': placeholder,
              'items': items,
  
          })
          return context
  
  plugin_pool.register_plugin(LienFooterAppPlugin)
  </code></pre>
  
  <p>Thanks a lot for your help!</p>