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);
}