title: getSupportFragmentManager().findFragmentById() doesn't return null even if it should
body: <p>Im building dynamic UI for tablets with two fragments side by side. </p>
  
  <p>I recognize which layout is displayed with <code>getSupportFragmentManager().findFragmentById(R.id.my_fragment)</code>, where my_fragments is 2nd fragment which is shown next to primary listfragment. But after some rotations and clicks getSupportFragmentManager().findFragmentById() returns fragment even if it shouldn't (another layout is displayed, only listfragment).</p>
  
  <pre><code>@Override
  public void onRSSMessageSelected(int position) {
      AppEngine.getInstance().setRSSMessagePosition(position);
      // The user selected the RSSMessge from the RSSMessagesList
  
      // Capture the detail fragment from the activity layout
      RSSMessageDetail fragment = (RSSMessageDetail)
              getSupportFragmentManager().findFragmentById(R.id.rssmessage_detail);
  
  
      // BUG: supportManager doesn't return null even if it should
      if (fragment!=null) {
          fragment.updateRSSMessageDetail();
  
      } else {
          fragment = new RSSMessageDetail();
          FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
          //add the transaction to the back stack so the user can navigate back
          transaction.replace(R.id.fragment_container, fragment);
          transaction.addToBackStack(null);
          transaction.commit();
      }
  }
  </code></pre>
  
  <p>layout:</p>
  
  <pre><code>&lt;FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:id="@+id/fragment_container"
      android:layout_width="match_parent"
      android:layout_height="match_parent" /&gt;
  </code></pre>
  
  <p>layout-land:</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="horizontal"
      android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;fragment android:name="cz.cvut.sabattom.fragment.RSSMessagesList"
                android:id="@+id/feed_messages_list"
                android:layout_weight="1"
                android:layout_width="0dp"
                android:layout_height="match_parent" /&gt;
  
      &lt;fragment android:name="cz.cvut.sabattom.fragment.RSSMessageDetail"
                android:id="@+id/rssmessage_detail"
                android:layout_weight="2"
                android:layout_width="0dp"
                android:layout_height="match_parent" /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>