title: How to remove "Delete" checkbox on "extra" forms in Django inline formset
body: <p>I'm using inline formsets in Django, and for each item showing one "extra" form, for adding another object.</p>
  
  <p>The forms for existing objects have "Delete" checkboxes, for removing that object, which makes sense.</p>
  
  <p>But also the "extra" forms have these "Delete" checkboxes... which makes no sense because there's nothing there to delete. Inline forms in the Django admin don't show these "Delete" checkboxes for "extra" forms.</p>
  
  <p>How can I remove these checkboxes on the "extra" inline forms?</p>
  
  <p>The inline formsets part of my template is something like this (<a href="https://github.com/philgyford/django-nested-inline-formsets-example/blob/master/publishing/books/templates/books/publisher_update.html#L54" rel="noreferrer">simplified, full version on GitHub</a>):</p>
  
  <pre><code>{% for bookimage_form in form.forms %}
    {% for hidden_field in bookimage_form.hidden_fields %}
      {{ hidden_field.errors }}
    {% endfor %}
  
    {{ bookimage_form.as_table }}
  {% endfor %}
  </code></pre>
  
  <p>And here's the "Delete" checkbox that seems superfluous:</p>
  
  <p><a href="https://i.stack.imgur.com/OA7EO.png" rel="noreferrer"><img src="https://i.stack.imgur.com/OA7EO.png" alt="example screenshot"></a></p>