Trackers with "Parent task" field set to "Read-only" should not be shown when adding a new subtask
If "Parent task" field of a tracker is set to read-only, the tracker should not be shown in the new issue form for subtasks because issues with such tracker cannot be a subtask.Steps to reproduce:
- Set the "Parent task" field of the tracker (hereafter called "Tracker-X") to "Read-only" on "Fields permissions" tab on "Workflow" page.
- Create a parent issue.
- Go to the new issue form for subtasks by clicking "Add" in "Subtasks" area of the parent issue.
- You can select Tracker-X in the new issue form. But the newly created issue never be a subtask because "Parent task" field of Tracker-X is read-only.