title: For some reason when I triple tap a TextInput, the tapped line isn't selected
body: <p>I am using kivy's TextInput in a project. In the documentation they say that TextInput.on_triple_tap is selecting the whole tapped line.
  But when I tripple tap a line in my text box, nothing is selected.</p>
  
  <p>I tried even to make my own on_triple_tap function, but it didn't work either.</p>
  
  <p>Am I missing something?</p>
  
  <p>First example - this should work, but it doesn't</p>
  
  <pre><code>from kivy.app import App
  from kivy.uix.textinput import TextInput
  
  
  class ManagerApp(App):
      def build(self):
          return TextInput(text='hello world')
  
  
  if __name__ == '__main__':
      ManagerApp().run()
  </code></pre>
  
  <p>second example - I tried to override the on_triple_tap, prints the 'reached' but doesn't select anything</p>
  
  <pre><code>from kivy.app import App
  from kivy.uix.textinput import TextInput
  
  
  class ManagerApp(App):
      def build(self):
          self.ti = TextInput(text='hello world', 
  on_triple_tap=self.my_triple_tap)
          return self.ti
  
      def my_triple_tap(self, ti):
          print 'reached'
          ti.select_all()
  
  
  if __name__ == '__main__':
      ManagerApp().run()
  </code></pre>