I have an online registration with a donation-based registration fee (zero to any amount is accepted).
Everything works great until I change the Payment Processor of the event registration. When I change it, the continue button of the registration form disappears as long as there is no donation amount entered, which then does not allow the user to register without donating anything.
I've set up 2 completely identical events, besides their Payment Processor to demonstrate the issue:
The missing button one: https://terranova.tamera.org/en/civicrm/event/register?reset=1&id=1946
Another thing to mention, is that the 2 Payment Processors are completely identical except for the PayPal's 'Pay' button image url, and their name.
My question is, what makes the continue button disappear in the 2nd one?