private void button5_Click(object sender, EventArgs e)
        {
            inventory inv = new inventory();

            inv.Show();
            this.WindowState = FormWindowState.Minimized;
        }
        private void button10_Click(object sender, EventArgs e)
        {
            inventory open = new inventory();

            open.Show();
            this.WindowState = FormWindowState.Minimized;
        }
        private void button15_Click(object sender, EventArgs e)
        {
            inventory open = new inventory();

            open.Show();
        }