disable subform

I have a CHANGE HISTORY subform on my TELCO ORDER FORM at https://creator.zoho.com/essistmgmt/form/1696/scriptbuilder/

I have disabled the subform

disable CHANGE_HISTORY;

I want users to see the CHANGE_HISTORY but not modify it

However, when I tested it, users can Add New rows & delete rows. How can I prevent them from doing that but still see the change history?