private void QLMuonTra_Click(object sender, EventArgs e)
{
QLTra form1 = new QLTra();
form1.Region = this.Region;
form1.Show();
this.Hide();
}
private void btnBack_Click(object sender, EventArgs e)
{
QLTra temp1 = new QLTra();
temp1.Region = this.Region;
temp1.Show();
this.Hide();
}