title: Material TabLayout elevation not working
body: <p>For some reason the elevation attribute does not seem to be working on the new TabLayout in the material design support library. Any ideas?
  XML:</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="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"&gt;
  
  &lt;android.support.design.widget.TabLayout
      android:id="@+id/tab_layout"
      android:layout_width="match_parent"
      android:layout_height="?attr/actionBarSize"
      android:elevation="6dp" /&gt;
  
  &lt;android.support.v4.view.ViewPager
      android:id="@+id/view_pager"
      android:layout_width="match_parent"
      android:layout_height="0dp"
      android:layout_weight="1" /&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>hooked up like this in a parent fragment:</p>
  
  <pre><code>ViewPager viewPager = (ViewPager) view.findViewById(R.id.view_pager);
  TabLayout tabLayout = (TabLayout) view.findViewById(R.id.tab_layout);
  AppPagerAdapter appPagerAdapter = new AppPagerAdapter(getChildFragmentManager());
  viewPager.setAdapter(appPagerAdapter);
  tabLayout.setupWithViewPager(viewPager);
  </code></pre>
  
  <p>image:
  <img src="https://i.stack.imgur.com/4v40A.png" alt="relevant image"></p>
  
  <p>The activity has a toolbar but this is outside of the fragment and should not affect the tablayout's ability to have a shadow:</p>
  
  <p>relevant activity xml:</p>
  
  <pre><code>&lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  tools:context="com.bluckapps.appinfomanager.ui.MainActivity"&gt;
  
  &lt;android.support.v7.widget.Toolbar
      android:id="@+id/toolbar"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="?attr/colorPrimary"
      android:elevation="6dp"
      android:minHeight="?attr/actionBarSize"
      tools:ignore="UnusedAttribute" /&gt;
  
  &lt;FrameLayout
      android:id="@+id/container"
      android:layout_width="match_parent"
      android:layout_height="0dp"
      android:layout_weight="1" /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>