Update Catalog Task's "State" upon closed complete/closed incomplete after SAVING

[Sam196]

Thank you for your help in advance!

Problem:

When a state is updated to "closed complete" or "closed incomplete" by the agent without saving it greys out (changes to read only). Agent has to refresh the entire page if he/she accidentally selects one of the options above, which is a big inconvenience when there's work notes and customer notes added.

What I want:

When an agent select "closed compete" or "closed incomplete" it shouldn't be read only. They should be able to change as they like. But once the agent SAVE or UPDATE the task with state "closed complete" or closed incomplete" state should change to read-only. Our policy is once a task is marked complete/incomplete we don't want it to be updated.

Screenshots below for reference. Again, thank you! 

Current UI Policy Setup:

When closed without saving it is changing to read-only:

[Sam196]

Thank you for replying Aman. In my case, how does ACL applies? We still want all agents to have the option to write but when the state is saved in closed we want it to be read-only.

[Aman Kumar S]

Yes, so the condition that I have highlighted, you can add in the condition.

Unless and until the state value is saved as closed, it will allow them to change the values on the form, until they submit.

This works exactly as you are looking.

[Aman Kumar S]

One more thing to consider here, if you make the fields read only using client script, it will still be editable from list layout even though when the state is closed. Something to think about regarding security