That value is readonly not the full field.
A new hook is added in https://github.com/shamim2883/front-end-pm/commit/dc41347194c1767d83526ee16d3b1fc8c09dba8a#diff-78cd5aa3783a74555c9938a2a81d01c6R328 but not yet merged with latest version. Next version you will get it merged and we can use that hook to make full field readonly.