Customer feedback told me that it was possible to navigate away from an unanswered question because the button was enabled. Silly mistake on my part, so I have just put an, "On Question End" action to enable the next button having first disabled it at page level. Works well, but not every time and I can't see why. Sometimes the button remains disabled. Successful results are identical in the actions as unsuccessful. I can't risk publishing and finding that users cannot navigate to the next page. Any ideas anyone please?