Django智能选择仍显示所有选项

Question

我第一次尝试使用django smart selects，但我无法让它工作。我想我一定是在设置中做错了什么，但我无法确定是什么。我有三种型号。客户、账单和订单。在订单中，用户应选择一个客户，然后BillTo选项应取决于所选客户。现在，我仍然看到所有BillTo选项，无论客户是谁。请有人帮我确定我在哪里犯了错误或遗漏了什么-这真的阻碍了我的项目

models.py

class Customers(models.Model):

    ultimate_consignee = models.CharField(max_length=100)

    def __str__(self):
        return self.ultimate_consignee

class BillTo(models.Model):

    ultimate_consignee = models.ForeignKey(Customers)
    c_address = models.CharField(max_length=1000)

    def __str__(self):
        return self.c_address

class Orders(models.Model):

    reference = models.CharField(max_length=50, unique=True) #REQUIRED
    ultimate_consignee = models.ForeignKey(Customers, blank=True) #REQUIRED
    c_address = ChainedForeignKey(BillTo, chained_field='ultimate_consignee', chained_model_field='ultimate_consignee', show_all=False, blank=True, default=None, null=True)

    def __str__(self):
        return self.reference

add_order.html

{% extends 'base.html' %}

{% block body %}

  <div class="container">
    <form method="POST" enctype='multipart/form-data'>
      <br>
      <h2>Order Information</h2>
      <br>
      {% csrf_token %}


    <div class="column_order">
        <label for="form.reference" class="formlabels">Reference ID: </label>
        {{ form.reference }}
        <br>
        <label for="form.ultimate_consignee" class="formlabels">UC: </label><br>
        {{ form.ultimate_consignee}}
        <br>
        <label for="form.c_address" class="formlabels">Ship To: </label>
        <br>
        {{ form.c_address}}
    </form>
  </div>
</div>

<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>

{% endblock %}