title: Cannot add multiple fragments to LinearLayout
body: <p>I am using a LinearLayout with a vertical orientation to list fragments. I add fragments to the container programmatically like this:</p>
  
  <pre><code>FragmentTransaction ft = fragmentManager.beginTransaction();
  
  Fragment fragment1 = new Fragment();
  ft.add(R.id.llContainer, fragment1);
  
  Fragment fragment2 = new Fragment();
  ft.add(R.id.llContainer, fragment2);
  
  ft.commit();
  </code></pre>
  
  <p>But it only shows the first fragment. Why?</p>