title: CollapsingToolbarLayout elevation not working and anchored FloatingActionButton not returning
body: <p>I've been trying to implement a layout <a href="http://material-design.storage.googleapis.com/publish/material_v_4/material_ext_publish/0B6Okdz75tqQsRTM1M1lCWWZiN2c/patterns-scrolling-techniques-flexible_space_xhdpi_003.webm" rel="nofollow">similar to this</a> from the material design guidelines, using the new <a href="http://android-developers.blogspot.com/2015/05/android-design-support-library.html" rel="nofollow">Android Design Support Library</a>. The <code>CollapsingToolbarLayout</code> seems to be the way to go, but it ignores any attempt to add elevation. Furthermore, if I set the height of the <code>AppBarLayout</code> to anything under about 144dp, the <code>FloatingActionButton</code> will pop out, but not return. Here's my xml:</p>
  
  <pre><code>&lt;android.support.design.widget.CoordinatorLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:fitsSystemWindows="true"&gt;
  
  &lt;android.support.design.widget.AppBarLayout
      android:id="@+id/appbar"
      android:layout_width="match_parent"
      android:layout_height="144dp"
      android:fitsSystemWindows="true"
      android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"&gt;
  
      &lt;android.support.design.widget.CollapsingToolbarLayout
          android:id="@+id/collapsing_toolbar"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          app:expandedTitleMarginEnd="72dp"
          app:expandedTitleMarginStart="72dp"
          app:layout_scrollFlags="scroll|exitUntilCollapsed"&gt;
  
          &lt;android.support.v7.widget.Toolbar
              android:id="@+id/toolbar"
              android:layout_width="match_parent"
              android:layout_height="?attr/actionBarSize"
              android:background="?attr/colorPrimary"
              android:paddingLeft="72dp"
              app:layout_collapseMode="pin"
              app:popupTheme="@style/ThemeOverlay.AppCompat.Light"/&gt;
  
      &lt;/android.support.design.widget.CollapsingToolbarLayout&gt;
  &lt;/android.support.design.widget.AppBarLayout&gt;
  
  &lt;android.support.v7.widget.RecyclerView
      android:id="@+id/recycler_view"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:scrollbars="vertical"
      app:layout_behavior="@string/appbar_scrolling_view_behavior"/&gt;
  
  &lt;android.support.design.widget.FloatingActionButton
      android:id="@+id/fab"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_margin="@dimen/fab_margin"
      android:src="@drawable/ic_person_add_white_24dp"
      app:borderWidth="0dp"
      app:fabSize="mini"
      app:layout_anchor="@id/appbar"
      app:layout_anchorGravity="bottom|left|start"/&gt;
  </code></pre>
  
  <p></p>