private void UpdatePivots()
{
Books.Navigate(typeof(Books), lastSelectedIndex - 1);
Handouts.Navigate(typeof(Handout), lastSelectedIndex - 1);
TeacherList.Navigate(typeof(Teachers), lastSelectedIndex - 1);
TestList.Navigate(typeof(Tests), lastSelectedIndex - 1);
Timings.Navigate(typeof(Timings), lastSelectedIndex - 1);
}