private void btnStartOver_Click(object sender, EventArgs e)
{
polygonBox.CreateGraphics().Clear(Color.White);
vertexManager = new PolygonVertexManager(polygonBox);
this.polygonBox.MouseClick += new System.Windows.Forms.MouseEventHandler(this.polygonBox_MouseClick);
}
public MainForm()
{
InitializeComponent();
vertexManager = new PolygonVertexManager(polygonBox);
}