Make Payment Document in Create Electronic Payment Files a Mandatory Field

Summary:

We require that the "Payment Document" field be mandatory on the "Create Electronic Payment Files" page.

We tried to change this setting in Page Composer, but it's not possible to edit this field. We've added a page that displays the controls that are currently unavailable for editing.

Version (include the version you are using, if applicable):26A

Is there another functional or configuration option to indicate the required field?