title: What happens to the current fragment once popBackStack() is called?
body: <p>If I have a fragment loaded, fragment A, and replace that fragment with fragment B, adding fragment A to the backstack like so:</p>
  
  <pre><code>public void replaceFragment(Fragment frag, String fragTag) {
      mFragmentTransaction = mFragmentManager.beginTransaction();
      mFragmentTransaction.replace(R.id.fragmentContainer, frag, fragTag);
      mFragmentTransaction.addToBackStack(null);
      mFragmentTransaction.commit();
  }
  </code></pre>
  
  <p>and then from fragment B I call:</p>
  
  <pre><code>popBackStackImmediate();
  </code></pre>
  
  <p>So that fragment A is loaded again. What happens to fragment B? In my code I am creating a new Fragment B object and loading it with my replaceFragment() method, and repeating the process. Am I creating a bunch of fragment B's every time I replace A with B and call popBackStack() or is B destroyed when popBackStack is called? Thanks.</p>