private void button1_Click(object sender, EventArgs e)
{
new_vendor f3 = new new_vendor();
f3.ChangeTab2();
f3.Show();
this.Hide();
}
private void vendor_list_Click(object sender, EventArgs e)
{
new_vendor f2 = new new_vendor();
f2.ChangeTab();
f2.Show();
this.Hide();
}