title: SlidingDrawer animation isn't visible
body: <p>I have some problem with <code>SlidingDrawer</code> animation.
  I have a <code>View</code></p>
  
  <h2>activity_main.xml</h2>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="horizontal"
  
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      &gt;
      &lt;RelativeLayout 
          android:id="@+id/rlGL"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"&gt;
  
      &lt;/RelativeLayout&gt;
  
  
      &lt;SlidingDrawer
          android:id="@+id/slidingDrawer1"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:topOffset="900dp"
          android:content="@+id/content"
          android:handle="@+id/handle"
          android:orientation="horizontal" 
          android:animateLayoutChanges="false"&gt;
  
          &lt;ImageView
              android:id="@+id/handle"
              android:layout_width="fill_parent"
              android:layout_height="wrap_content"
              android:src="@drawable/add" /&gt;
  
          &lt;LinearLayout
              android:id="@+id/content"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:measureWithLargestChild="true"
              android:orientation="vertical" 
              android:background="#171717"&gt;
  
          &lt;Button
              android:id="@+id/bOk"
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:text="@string/ok"  
              android:textSize="48sp"&gt;
  
          &lt;/Button&gt;
  
      &lt;/LinearLayout&gt;
      &lt;/SlidingDrawer&gt;
  
  &lt;/FrameLayout&gt;
  </code></pre>
  
  <p>This "empty" <code>RelativeLayout</code> I use for <code>SurfaceView</code> (for camera preview) and <code>GLSurfaceView</code> (for OpenGL scene with transparent background). There is a code:</p>
  
  <h2>MainActivity.java</h2>
  
  <pre><code>...
  setContentView(R.layout.activity_main);
  
  relLayout = (RelativeLayout) findViewById(R.id.rlGL);
  
  
  mGLSurfaceView = new MyGlSurfaceView(this); 
  mGLSurfaceView.getHolder().setFormat(PixelFormat.TRANSLUCENT);
  relLayout.addView(mGLSurfaceView, new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
  
  preview = new SurfaceView(this);        
  surfaceHolder = preview.getHolder();
  surfaceHolder.addCallback(this);
  relLayout.addView(preview, new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
  ...
  </code></pre>
  
  <p>The problem is, that after clicking on handle image of the drawer, it disappears for a moment (while the animation runs), and then appears in opened state. Why does it happen?</p>