Commerce Checkout ignores CAPTCHA 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?
I don't know exactly how your CAPTCHA module works, but one possible problem is that the checkout form uses button level validate / submit handlers instead of the form level handlers your CAPTCHA module might be working through. In Drupal forms, if the button used to submit the form has those handlers, the form level handlers will be ignored.