I have set up a webform to take event registrations. A user can click through to the payment form without selecting an event and can click submit. This doesn't register them for the event, but I would like to stop this. Due to the way I have setup the form I cannot use required fields on event selection. The webform is pretty complex.
Ideally, I would remove the submit button on the payment page unless the amount is greater than $0. Is this possible?