public void StartSearch ()
{
if (originalSections != null)
return;
searchBar.BecomeFirstResponder ();
originalSections = Root.Sections.ToArray ();
originalElements = new Element [originalSections.Length][];
for (int i = 0; i < originalSections.Length; i++)
originalElements [i] = originalSections [i].Elements.ToArray ();
}