private void RemoveSpecialty_Click(object sender, RoutedEventArgs e)
        {
            int SelectedSpecialtyId;

            SelectedSpecialtyId = SpecialtiesGrid.SelectedIndex;
            Specialty SelectedSpecialty;

            SelectedSpecialty = (Specialty)SpecialtiesGrid.Items[SelectedSpecialtyId];
            dbl.RemoveSpecialty(SelectedSpecialty);
            Specialties.Remove(SelectedSpecialty);
        }