If the Unity Form contains a CAPTCHA control, a CAPTCHA is Completed setting option is displayed in the Preview Options pane. In order to fully test forms with CAPTCHA controls, you must mark the control as complete because the CAPTCHA control is not fully functional in test drive mode and the form cannot be submitted if the CAPTCHA control is not complete. The CAPTCHA control will render as a placeholder image in test drive. If you change the CAPTCHA is Completed selection, you must click Refresh to test the form with that setting.