I have seen various solutions proposed for things similar to what I want to do, but not exactly. I want to create a transition that spawns a subtask, and have the Assignee for the subtask be something chosen in a transition screen.
The closes solution I've seen is Create Sub-task on Transition plugin, but there the choices for Assignee for the sub-task are Current User, Parent reporter, Parent assignee, Project Lead or Specific User. I am fine to have a custom user field that this plugin can grabe the user from, but that's not an option.
How do I get the subtask to have an assignee chosen in the transition that doesn't force me to make the parent have the same assignee?