AppColl includes a "Transient Event" DeadlineType that was created responsive to input I provided several years ago. A transient event is just like a normal event except that it comes into existence and then immediately deletes itself--however, it triggers any follow-on tasks that might be needed and sends out notifications associated with it prior to disappearing.
It would be very nice if the Tasks framework were to be updated so that any TaskType could be made to be "transient," i.e., made to self-delete once no longer "Open." For example, every TaskType definition could have a "Transient" (or "Delete Once Closed" if a more descriptive name is desired) setting, e.g., a checkbox, that can be checked for a TaskType if that TaskType is to self-destruct once closed out.
This would be a little different than how the existing Transient Event DeadlineType works in that non-Event TaskTypes with this setting enabled would not immediately self-delete, but would stay visible on the docket until closed out. However, the existing Transient Event DeadlineType should be implementable under this new framework as well, e.g., as a normal Event DeadlineType that has the "Transient" setting enabled--since Events are tasks that instantly complete themselves, the "transient"-enabled Event should work like the current Transient Event DeadlineType.
The benefit to having this setting is that it would allow for intermediate deadlines, e.g., reminder deadlines, to be auto-closed and then disappear from the docket, as opposed to cluttering it up in a "completed" state. We like to have our docket be relatively streamlined, e.g., free of low-value entries. An advance reminder of an upcoming foreign deadline, for example, is useful to have on the docket, but once that reminder is in the past, it really isn't something we need to keep seeing.... Being able to have it automatically clean itself off the docket would be a nice capability to have (and would save our docketing department time and effort).