Would it be possible, please, to give the option to set the "Order reference" field as required so it cannot be left blank? This would mean that all shipments can be referenced to their corresponding delivery note, pick list, or whatever other internal reference a company uses to identify shipments sent using Click & Drop. As a bonus, you could add an editable description so that the user can add what that reference is in brackets - i.e. "Order reference (delivery note)".