title: Button doesn't appear in android appwidget layout
body: <p>I have this xml file as a layout of an appwidget: </p>
  
  <pre><code>    &lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical"
      android:background="@android:color/black" &gt;
  
      &lt;!-- ListView to be shown on widget --&gt;
      &lt;ListView
          android:id="@+id/listViewWidget"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content" /&gt;
  
      &lt;Button
          android:id="@+id/refresh_appwidget"
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:text="refresh"
   /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>The button is not displayed, and I don't know the cause. I tested layout_with match_parent but always the same result.</p>
  
  <p>How can I fix this issue?</p>