title: Cannot find fragment by tag
body: <p>I have some fragments, named <code>frag1</code> till <code>frag12</code>. They're made/called by order. So, after <code>frag1</code> replaced by <code>frag2</code>, <code>frag2</code> replaced by <code>frag3</code>, so on. At <code>frag10</code>, I need to go back to <code>frag2</code>. But I always got <code>null</code> when I tried to access <code>Frag2</code> by its <code>tag</code>.</p>
  
  <p>First, when moving from <code>frag1</code> to <code>frag2</code>, I did it like this</p>
  
  <pre><code>FragmentTransaction transaction =  getFragmentManager().beginTransaction(); 
  transaction.replace(((FrameLayout) container).getId(), 
                          new Frag2(getActivity(), container), 
                          "frag2");
  transaction.addToBackStack(null);
  transaction.commit();
  </code></pre>
  
  <p>Then, at <code>frag10</code>, I tried this</p>
  
  <pre><code>Fragment frag2 = getChildFragmentManager().findFragmentByTag("frag2");
  </code></pre>
  
  <p>and the result was, <code>frag2</code> was <code>null</code>.  </p>
  
  <p>What might have happened? Where's <code>Frag2</code>?</p>