protected virtual void DaysToTeach_button_Click(object sender, EventArgs e)
        {
            ChooseDaysToTeach_Form form = new ChooseDaysToTeach_Form(ref emp);

            this.Hide();
            form.FormClosed += new FormClosedEventHandler(FormClosedHandling);
            form.ShowDialog();
        }
        protected override void DaysToTeach_button_Click(object sender, EventArgs e)
        {
            EmpInterface           emp  = this.lecturer;
            ChooseDaysToTeach_Form form = new ChooseDaysToTeach_Form(ref emp);

            this.Hide();
            form.FormClosed += new FormClosedEventHandler(FormClosedHandling);
            form.ShowDialog();
        }