Authorize.net: How to set the "authorization only" option

When I selected the "authorization only" option under the Authorize.net payment gateway and tested this form: https://form.jotform.com/53526081638155 it still charged the card. 

Have I set this feature up incorrectly?

I tested the integration, however, I was unable to replicate your issue.

If you are still building your form, you can try removing the payment integration and adding it again, then enable the "authorize only" option and test it again.

Do let us know if it works, if not, we will take a look again in your form.