title: Error: No resource found that matches the given name: attr 'abBackground'
body: <p>I'm using <code>ActionBarSherlock</code>, and want to use a custom background for both the ActionBar and the content view below it. When I try this, the background fills the whole screen, including the actionbar:</p>
  
  <pre><code>&lt;style name="MyTheme" parent="@style/Theme.Sherlock"&gt;
      &lt;item name="android:windowBackground"&gt;@drawable/background&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>So, from <a href="https://stackoverflow.com/a/9162297/675383">this answer</a>, I tried to add <code>abBackground</code> to the theme:</p>
  
  <pre><code>&lt;style name="MyTheme" parent="@style/Theme.Sherlock"&gt;
      &lt;item name="android:windowBackground"&gt;@drawable/background&lt;/item&gt;
      &lt;item name="abBackground"&gt;@drawable/bg_button_idle&lt;/item&gt;
  &lt;/style&gt;
  </code></pre>
  
  <p>However, I get the error</p>
  
  <blockquote>
    <p>Error: No resource found that matches the given name: attr 'abBackground'.</p>
  </blockquote>
  
  <p>Why is this, and how can I fix it?</p>