opts.tasks = task.Descendents()
	slices.SortStableFunc(opts.tasks, func(a, b *trace.UserTaskSummary) int {
		aStart, bStart := parsed.startTime(), parsed.startTime()
		if a.Start != nil {
			aStart = a.Start.Time()
		}
		if b.Start != nil {
			bStart = b.Start.Time()
		}
		if a.Start != b.Start {
			return cmp.Compare(aStart, bStart)
		}
		// Break ties with the end time.
		aEnd, bEnd := parsed.endTime(), parsed.endTime()