Hello there, @ducrot64.
Yes, if the custom field is empty or has never had any information entered, it will not appear on the Custom Field section when you edit the customer.
However, when a custom field has been used on a transaction or contains data, it will still appear when editing those customers—even though it's marked inactive.
The inactive status prevents it from appearing on new customers or transactions, but doesn't hide existing data.
If you have any follow-up questions or any other concerns, please don't hesitate to use the Reply button.