public SimpleDropSink()
 {
     this.timer.Interval = 250;
     this.timer.Tick    += new EventHandler(this.timer_Tick);
     this.CanDropOnItem  = true;
     this.FeedbackColor  = Color.FromArgb(180, Color.MediumBlue);
     this.billboard      = new BillboardOverylay();
 }
        /// <summary>
        /// Make a new drop sink
        /// </summary>
        public SimpleDropSink()
        {
            this.timer = new Timer();
            this.timer.Interval = 250;
            this.timer.Tick += new EventHandler(this.timer_Tick);

            this.CanDropOnItem = true;
            //this.CanDropOnSubItem = true;
            //this.CanDropOnBackground = true;
            //this.CanDropBetween = true;

            this.FeedbackColor = Color.FromArgb(180, Color.MediumBlue);
            this.billboard = new BillboardOverylay();
        }