private void button1_Click(object sender, EventArgs e)
        {
            Row r;

            if (Rows.Count > 0)
            {
                r = new Row(Rows[Rows.Count - 1].Item2, DateTime.Today, 20);
            }
            else
            {
                r = new Row(DateTime.Today, DateTime.Today, 20);
            }
            Rows.Add(r);
            IntervalRow c = new IntervalRow(r)
            {
                Dock = DockStyle.Top
            };

            c.XClick += OnXClick;
            c.Change += OnRowChange;
            panel1.Controls.Add(c);
            panel1.Controls.SetChildIndex(c, 0);
            panel1.Invalidate();
            Change?.Invoke(this, e);
        }
 public IntervalPercentage()
 {
     InitializeComponent();
     panel1.Controls.Clear();
     foreach (Row row in Rows)
     {
         IntervalRow c = new IntervalRow(row)
         {
             Dock = DockStyle.Top
         };
         c.XClick += OnXClick;
         c.Change += OnRowChange;
         panel1.Controls.Add(c);
     }
     Invalidate();
 }