Whoa, what an interesting edge case you found here… I don’t know that there is any simple way to do this. You could do a pretty hacky workaround that relies on our insertion order; that is, when you set the parent on a task with setParent it always goes at the top of the list of subtasks. You could get the subtasks on the task, call setParent with "parent"=null on them to unset them, then call setParent again in reverse-sorted order in order to rebuilt the subtasks from “the bottom up”. That’s annoying, but it’d probably work.