WordPress form should be inside the tab

I want the default wordpress comment form (i.e. fields) inside the WordPress tab in the Comments Plus section. Currently, the form is visible after the Comments Plus section thus even Twitter or Google is selected, these forms appear.

I tried ‘comment_form’ and the pair ‘comment_form_before’ and ‘comment_form_after’ hooks but still fails.

I also remove the HTML fields in assumption that Comments Plus includes the WordPress form automatically but removing these fields will render no HTML form.