The following code shows the lack of implementation of the Arrow Series's Clicked method:

		private Arrow series;
		public Form1()
		{
			InitializeComponent();

			series = new Arrow(tChart1.Chart);
			series.FillSampleValues();
			tChart1.MouseMove += TChart1_MouseMove;
		}

		int oldIndex = -1;
		private void TChart1_MouseMove(object sender, MouseEventArgs e)
		{
			int index = series.Clicked(e.X, e.Y);
			Color oldColor = Utils.EmptyColor;
			if (index > -1)
			{
				oldColor = series[index].Color;
				series[index].Color = Color.Red;
				if (oldIndex > -1)
				{
					series[oldIndex].Color = oldColor;
				}
				oldIndex = index;
			}

			tChart1.Invalidate();
		}