title: Fragment over another fragment issue
body: <p>When I'm showing one fragment (which is full screen with <code>#77000000</code> background) over another fragment (let's call it main), my main fragment still reacts to clicks (we can click a button even if we don't see it).</p>
  
  <p><strong>Question</strong>: how to prevent clicks on first (main) fragment?</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>Unfortunately, I can't just hide main fragment, because I'm using transparent background on second fragment (so, user can see what located behind).</p>