[2.1]: Post editor ignores "Show subjects in topic"

[LexArma]

Basic Information

Small thing, but if the admin has hidden reply subjects in topic, perhaps the editor should not allow editing them either.
Currently editing the subject line of a reply allows for semi-hidden added content, which can be hard to spot for moderators/admin.
Suggestion, if "Show subjects in topic" is disabled, simply use the default re: subject and don't allow editing it.

Steps to reproduce

Toggle Admin -> Forum -> Posts and Topics -> Topic Settings -> Show subjects in topics, and post a new reply to see how the editor behaves.

Expected result

The editor should IMHO, respect the setting and allow/disallow editing the subject line accordingly.

Actual result

Currently the editor always allows editing the subject.

Version/Git revision

2.1.4

Database Engine

All

Database Version

No response

PHP Version

No response

Logs

No response

Additional Information

No response