I'm running a Drupal 7 web-site with Drupal Commerce and CAPTCHA modules. I have a CAPTCHA challenge set up on the checkout page. Although an incorrect solved CAPTCHA will show an error, the CAPTCHA still gets ignored when I click "Continue to next step", thus the CAPTCHA can be left empty and the site will still take the user to the next form.
The CAPTCHA is added in the CAPTCHA config (admin/config/people/captcha) to the form "commerce_checkout_form_checkout".
Things I've tried (but didn't help):
- Add a CAPTCHA field to the form programmatically;
- Add "[required] => 1" to said field;
- Tried with both the Math CAPTCHA and reCAPTCHA.
How can I make CAPTCHA work on Drupal Commerce's checkout form?