title: Fragments displayed over each other
body: <p>I've got an Activity with a DrawerLayout, using the guidelines from <a href="http://developer.android.com/training/implementing-navigation/nav-drawer.html">http://developer.android.com/training/implementing-navigation/nav-drawer.html</a>.</p>
  
  <p>When I click on an drawerItem, I replace the current view with the new fragment:</p>
  
  <pre><code>Fragment fragment;
  Bundle args = new Bundle();    
  fragment = new NewsListFragment();
  args.putInt("category", position);
  
  // Insert the fragment by replacing any existing fragment
  FragmentManager fragmentManager = getSupportFragmentManager();
  fragmentManager.beginTransaction()
                     .replace(R.id.content_frame, fragment)
                     .commit();        
  mDrawerList.setItemChecked(position, true);
  </code></pre>
  
  <p>Now, sometimes the old fragment is not replaced but the new fragment is placed on top of the old one: </p>
  
  <p><a href="http://img15.imageshack.us/img15/3179/1kqj.png">http://img15.imageshack.us/img15/3179/1kqj.png</a></p>
  
  <p>Why is this, and how to solve this problem?</p>
  
  <p>Relevant XML:</p>
  
  <pre><code>&lt;!-- The main content view --&gt;
  &lt;LinearLayout 
      android:id="@+id/rlMain"
      android:layout_width="fill_parent"
      android:orientation="vertical"
      android:layout_height="fill_parent"&gt;
  
      &lt;FrameLayout
          android:id="@+id/content_frame"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent" 
          android:layout_weight="1"&gt;
      &lt;/FrameLayout&gt;
  </code></pre>
  
  <p>This only happens sometimes, and I haven't found a flow to reproduce this yet. The app doesn't support rotating, so it won't happen there.</p>