hi! 
I use Cloud JIRA
when I use server JIRA, I can set properties on workflow 'jira.permission.assignable.projectrole.1'
but, I set same properties, I can just show all users in the assignee dropdown
In short
- I want to assign to specific project role user (if set wrong assignee, don't change status)
- I only want to see people with a specific role in the dropdown.
Let me know if you have any good ideas