title: I want to make a sticky menu using kivy's screenmanager
body: <p>I want to make a stickymenu like this</p>
  
  <p><img src="https://i.stack.imgur.com/c1JIj.jpg" alt="Here is image"></p>
  
  <p>yeah looks like iosApp menubar. I already know i should use screenmanager but i understood it can use only Class of Screen. If i hope use in Boxlayout class.But i dont know it. If somebody tell me how make like this menu.</p>
  
  <p>I forgot to write important things.
  The menu that I want to make is in a state where it is fixed without making a transition for each menu when making a page transition.</p>