private void Button2_Click(object sender, EventArgs e)
{
this.Hide();
st_registration_form stregform = new st_registration_form();
stregform.FormClosed += (s, args) => this.Close();
stregform.Show();
}
private void PictureBox8_Click(object sender, EventArgs e)
{
st_registration_form stregform = new st_registration_form();
stregform.Show();
}