How to disable create sub -task when parrent issue is closed

[Lotus Support]

How can i prevent user from creating sub-tasks from closed parrent issues?

I read that it shuold be possible to do this with 

Workflow Step Properties

but i am not sure how to do it?

[Artur Karpiński]

https://community.atlassian.com/t5/JIRA-questions/Making-a-closed-issue-read-only/qaq-p/365063

[Lotus Support]

This just makes the parent issue non-editable...I would like the user to get warning message when creating sub-task that parrent issue is closed, and not allow him to create sub-task for closed task.

Or just to disable the option to create sub-task

[vishal]

@ Lotus Support

Have you got the answer for displying error message?