Can't change Payment Method on Payment Form after invoice selection

Support
1

On the Payment Form (choose Enter Payment from dropdown) once an invoice is selected the Payment Method dropdown greys out and can no longer be selected.
As a workaround I did this:
Change line 12 of /application/modules/payments/view/form.php from:
$(’#payment_method_id’).attr(‘disabled’, ‘disabled’);
To:
// $(’#payment_method_id’).attr(‘disabled’, ‘disabled’);

But not sure what the reason was for disabling the field in the first place so I’m not sure what I’ve opened up for the client.

2

The field is automatically set if you choose a payment method inside the invoice.

3

I thought that might be the case. The user isn’t setting the payment method (so the dropdown when viewing the invoice still says “Select the Payment Method”).
payment_method in ip_invoices in the database is getting saved with a value of 0, not NULL so I think that’s why the check fails. payment_method seems to be set as an integer.

Solution?
Change line 11 in /application/modules/payments/view/form.php from:
$(’#payment_method_id option[value="’+invoice_payment_methods[invoice_identifier]+’"]’).attr(‘selected’, ‘selected’);
$(’#payment_method_id’).attr(‘disabled’, ‘disabled’);

To:
if (invoice_payment_methods[invoice_identifier] != 0) {
$(’#payment_method_id option[value="’+invoice_payment_methods[invoice_identifier]+’"]’).attr(‘selected’, ‘selected’);
$(’#payment_method_id’).attr(‘disabled’, ‘disabled’);
};