4. Stocker - Form1_DoubleClick event

To enable Form1_DoubleClick event for form Form1
   
private void Form1_DoubleClick(object sender, EventArgs e)
        {
            Environment.Exit(0);        // double click on form to end application- just for quick exit when testing
        }

it is needed to add line in bold after line in plain in Form1.Designer.cs via Solution explorer

            this.Load += new System.EventHandler(this.Form1_Load);
            this.DoubleClick += new System.EventHandler(this.Form1_DoubleClick);