/// <summary>
        /// Prepare for data gathering. Add duration box.
        /// </summary>
        public override void Prepare()
        {
            if (Prepared)
            {
                return;
            }
            Prepared = true;

            ExtraBoxes.SmoothFragmentTimer ftimer = new ExtraBoxes.SmoothFragmentTimer(Offset, Duration);
            Tracks.AddChild(ftimer);
        }