title: FAB is hiding under Bottom Sheet
body: <p>I have following XML:</p>
  
  <pre><code>&lt;android.support.design.widget.CoordinatorLayout
      android:id="@+id/sliding_layout"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:layout_below="@id/app_bar"&gt;
  
      &lt;LinearLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:orientation="vertical"
          app:layout_behavior="@string/appbar_scrolling_view_behavior"&gt;
  
          &lt;fragment
              android:id="@+id/fragment1"
              android:name="com.xyz.Fragment1"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:gravity="center"
              tools:layout="@layout/fragment_layout1" /&gt;
      &lt;/LinearLayout&gt;
  
      &lt;LinearLayout
          android:id="@+id/layoutBottomSheet"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:elevation="@dimen/global_margin"
          android:orientation="vertical"
          app:layout_behavior="@string/bottom_sheet_behavior"&gt;
  
          &lt;fragment
              android:id="@+id/fragment2"
              android:name="com.xyz.Fragment2"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:gravity="center|top"
              tools:layout="@layout/fragment_layout2" /&gt;
      &lt;/LinearLayout&gt;
  
      &lt;android.support.design.widget.FloatingActionButton
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginEnd="@dimen/global_margin"
          android:layout_marginRight="@dimen/global_margin"
          android:src="@drawable/ic_add_white_24dp"
          app:borderWidth="0dp"
          app:elevation="4dp"
          app:layout_anchor="@id/layoutBottomSheet"
          app:layout_anchorGravity="top|right|end" /&gt;
  &lt;/android.support.design.widget.CoordinatorLayout&gt;
  </code></pre>
  
  <p>The layout should appear as, <code>Fragment1</code> then below that <code>Fragment2</code> and FAB is anchored to <code>Fragment2</code> but, <strong>above</strong> <code>Fragment2</code> and not <strong>under</strong> it.</p>
  
  <p>Actually it is showing as,</p>
  
  <p><a href="https://i.stack.imgur.com/qvZTc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qvZTc.png" alt="screenshot"></a></p>
  
  <p>What is going wrong? Any idea?</p>