private void ItemsBox_CheckedChanged(object sender, EventArgs e)
        {
            addItemButton.Show();
            dataGridView2.BringToFront();
            ItemPanel.BringToFront();
            dataGridView1.Rows.Clear();

            dataGridView2.Rows.Clear();
            foreach (var item in _shipper.ShowItems())
            {
                dataGridView2.Rows.Add(item.ItemID, item.Name, item.Price, item.OnStock);
            }

            if (textBox1.Text.Length != 0)
            {
                updateItemButton_Click_1(sender, e);
                textBox1.Clear();
                textBox2.Clear();
                textBox3.Clear();
                textBox4.Clear();
                textBox5.Clear();
            }
        }