Payment Due goes negative

I noticed that when the order amount (subtotal) is lower than the discount the Payment Due goes negative.
By my opinion that must not be possible and Payment Due should be set to 0.00 in such cases.
I know this is a situation one needs to avoid, but just in case it does happen for some reason, the system should never go negative.

Thanks,
Harry

That's a nice discount! :) You might want to set a minimum subtotal, or a percentage discount.
Indeed the frontend shouldn't be able to go negative. I can add a condition for that in the next version. Backend is another story.