title: Fragment is not being replaced but put on top of the previous one
body: <p>Activity:        </p>
  
  <pre><code>FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
  
  Fragment1 fragment = new Fragment1();
  Fragment2 fragment2 = new Fragment2();
  
  transaction.replace(R.id.Fragment1, fragment);
  transaction.addToBackStack(null);
  transaction.commit();
  
  FragmentTransaction transaction2 = getSupportFragmentManager().beginTransaction();
  transaction2.replace(R.id.Fragment1, fragment2);
  transaction2.addToBackStack(null);
  transaction2.commit();
  </code></pre>
  
  <p>Code in the view:</p>
  
  <pre><code>&lt;fragment
      android:id="@+id/Fragment1"
      android:name="com.landa.fragment.Fragment1"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_alignParentBottom="true"
      android:layout_alignParentLeft="true"
      android:layout_below="@+id/include1" /&gt; 
  </code></pre>
  
  <p>The problem is, the content doesn't really get replaced - it gets put on top (so it overlaps).</p>
  
  <p>When I click back, the first fragment gets shown properly (without the second), but initially both are visible (I want only the last one to be visible).</p>
  
  <p>What am I missing here?</p>