title: Transparent action bar not being fully transparent. (Leaves weirdbox)
body: <p>I've tried setting the action bar I custom-made for my application to be transparent. However instead of being completely transparent, it leaves a weird elevation shadow:</p>
  
  <p><a href="http://puu.sh/rdYyb/04ce0147f6.jpg" rel="nofollow">http://puu.sh/rdYyb/04ce0147f6.jpg</a></p>
  
  <p><strong>The XML for the bar:</strong></p>
  
  <pre><code>&lt;android.support.design.widget.AppBarLayout
      android:id="@+id/appbarlayout"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:theme="@style/AppTheme.AppBarOverlay"&gt;
  
      &lt;android.support.v7.widget.Toolbar
          android:id="@+id/toolbar"
          android:layout_width="match_parent"
          android:layout_height="?attr/actionBarSize" /&gt;
  
  &lt;/android.support.design.widget.AppBarLayout&gt;
  
  
  &lt;android.support.design.widget.FloatingActionButton
      android:id="@+id/OverviewFAB"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="bottom|end"
      android:layout_margin="@dimen/fab_margin"
      android:src="@drawable/ic_add_alert" /&gt;
  
  &lt;RelativeLayout
      android:id="@+id/main_fragment_container"
      android:layout_width="match_parent"
      android:layout_height="wrap_content" /&gt;
  </code></pre>
  
  <p><strong>The styles XML for my themes:</strong></p>
  
  <pre><code>&lt;!-- Base application theme. --&gt;
  &lt;style name="AppTheme" parent="Theme.AppCompat.NoActionBar"&gt;
      &lt;!-- Customize your theme here. --&gt;
      &lt;item name="colorPrimary"&gt;@color/colorPrimary&lt;/item&gt;
      &lt;item name="colorPrimaryDark"&gt;@color/colorPrimaryDark&lt;/item&gt;
      &lt;item name="colorAccent"&gt;@color/colorAccent&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar"&gt;
      &lt;item name="android:windowActionBarOverlay"&gt;true&lt;/item&gt;
      &lt;item name="android:windowActionBar"&gt;false&lt;/item&gt;
      &lt;item name="windowNoTitle"&gt;true&lt;/item&gt;
  &lt;/style&gt;
  
  &lt;style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light"&gt;&lt;/style&gt;
  </code></pre>
  
  <p></p>
  
  <p><strong>How I programatically try to remove the elevation and background in the activity:</strong></p>
  
  <pre><code>    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
      AppBarLayout appBarLayout = (AppBarLayout) findViewById(R.id.appbarlayout);
      appBarLayout.setElevation(0);
      toolbar.setElevation(0);
      appBarLayout.setBackgroundColor(ContextCompat.getColor(this, android.R.color.transparent));
      toolbar.setBackgroundColor(ContextCompat.getColor(this, android.R.color.transparent));
  </code></pre>
  
  <p>But despite all this the box (shown in the link) still persists... I'm not sure what's going on? Does anyone see anything wrong in my code?</p>