Tracking planned completion dates for tasks with different statuses
The attribute Track deadlines for tasks with this status defines whether or not a task with the given status will be considered overdue after the planned completion date set in the task.
If Track is selected — which is the default — then if a task has the given status after the planned completion date, the task will have an Overdue flag and will be displayed as such in the interface.
If Don't track is selected, the task will not be overdue if it has the given status after the planned completion date.
You can change this setting when creating or editing a status.