You can not grey out a filed in a post funciton because post-function works after you executed your request to Jira.
If you have Adaptivist Scriptrunner and you are not on Cloud, you could use behaviours
I’m a designer on the Jira team. For a long time, I’ve fielded questions from other designers about how they should be using Jira Software with their design team. I’ve also heard feedback from other ...
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