private void back_button_Click(object sender, EventArgs e)
{
login_interface li = new login_interface();
change_password cp = new change_password();
MainClass.ShowWindow(li, cp, MDI.ActiveForm);
}
private void change_password_button_Click(object sender, EventArgs e)
{
change_password fp = new change_password();
MainClass.ShowWindow(fp, MDI.ActiveForm);
}