title: Why is my second LinearLayout not showing?
body: <p>I have just decided to try out the Android SDK, so I installed it and now I'm trying to make a simple interface using an XML file for a calculator I've made and that I might port to Android.</p>
  
  <p>Here a first draft of the XML file I want to use:</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      &gt;
    &lt;TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:lines="3"
        android:text="To evaluate an expression, type it below."
        /&gt;
    &lt;EditText
        android:id="@+id/entry"
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text=""
        /&gt;
    &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:orientation="horizontal"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          &gt;
      &lt;Button
      android:id="@+id/btnFunctions"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Functions"
      /&gt;
      &lt;Button
      android:id="@+id/btnConversions"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Conversions"
      /&gt;
      &lt;Button
      android:id="@+id/btnConstants"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Constants"
      /&gt;
    &lt;/LinearLayout&gt;
    &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
          android:orientation="horizontal"
          android:layout_width="fill_parent"
          android:layout_height="fill_parent"
          &gt;
      &lt;Button
      android:id="@+id/btnGraphs"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Graphs"
      /&gt;
      &lt;Button
      android:id="@+id/btnStats"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Stats"
      /&gt;
    &lt;/LinearLayout&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>However, when I run <code>ant install</code> and try out the app on the emulator, the last two buttons in the last (nested) LinearLayout, btnGraphs and btnStats, do not show up at all (the rest is fine).</p>
  
  <p>What am I doing wrong?</p>