title: How do I detect tab was touched in xamarin forms TabbedPage
body: <p>How could I detect tab was touched in xamarin forms TabbedPage?
  (which is different from page changed detection which I figured how to detect)</p>
  
  <p>Here is why:
  I'm trying to work around a rather ugly tabbed page overflow UI
  (the ugly scroller that shows up on the right over the tabbar
  whenever there are >5 tabs)
  So the 5th tab press shows a custom menu, second press hides that menu, etc.</p>
  
  <p>Thanks!</p>