private void button2_Click(object sender, EventArgs e)
        {
            TicketSupplier form = new TicketSupplier();

            form.Show();
            this.Close();
        }
 private void pictureBox1_Click(object sender, EventArgs e)
 {
     if (lights.Equals(d))
     {
         //this.BackgroundImage = dark;
         MessageBox.Show("Συγχωρέστε μας είμαστε κλειστά!");
     }
     else
     {
         //this.BackgroundImage = bright;
         TicketSupplier form = new TicketSupplier();
         form.Show();
         this.Close();
     }
 }