If I try to change the travelers ‘fields and then the billing fields, changes on the travelers’ fields are lost.
Furthermore it is not possible to make data of non-leading passengers mandatory.
What do you sell to do this software?
Glad that you figured out your first issue by your self. As for query related to the form field, yes currently the forms for other traveler is not compulsory. But we will add the filter in the next release using which you will be able to nake the form compulsory for other travelers as well.