public virtual Pad AddPad(double x1, double y1, double x2, double y2)
{
var pad = new Pad(this, x1, y1, x2, y2);
pad.Name = $"Pad {this.fPads.Count + 1}";
pad.ForeColor = this.fPadsForeColor;
pad.Zoom += ZoomChanged;
this.fPads.Add(pad);
return Chart.fPad = pad;
}