title: Why toolbar has no elevation?
body: <p>I've been trying to use the new design library and I have a toolbar instead of deprecated action bar. The problem is that the toolbar has no elevation. I added elevation everywhere in layouts, in code, I even added AppBarLayout. Nothing works. I'm testing both on Lollipop and Kitkat. </p>
  
  <p>Any help is highly appreciated.</p>
  
  <p>my style.xml</p>
  
  <pre><code>&lt;resources&gt;
  
      &lt;style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar"&gt;
  
          &lt;item name="colorPrimary"&gt;@color/ColorPrimary&lt;/item&gt;
          &lt;item name="colorPrimaryDark"&gt;@color/ColorPrimaryDark&lt;/item&gt;
          &lt;item name="windowActionBar"&gt;false&lt;/item&gt;
  
          &lt;!-- Customize your theme here. --&gt;
      &lt;/style&gt;
  
  &lt;/resources&gt;
  </code></pre>
  
  <p>activity_main.xml</p>
  
  <pre><code>    &lt;android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
                                          android:id="@+id/drawer_layout"
                                          android:layout_width="match_parent"
                                          android:fitsSystemWindows="true"
                                          android:layout_height="match_parent"&gt;
      &lt;RelativeLayout
              android:id="@+id/container"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              &gt;
          &lt;include
                  android:elevation="7dp"
                  android:id="@+id/tool_bar"
                  layout="@layout/app_bar"
                  &gt;&lt;/include&gt;
      &lt;/RelativeLayout&gt;
      &lt;android.support.design.widget.NavigationView
              android:id="@+id/nav_draw"
              android:layout_width="wrap_content"
              android:layout_height="match_parent"
              android:layout_gravity="start"
              app:headerLayout="@layout/drawer_header"
              app:menu="@menu/drawer" /&gt;
      &lt;/android.support.v4.widget.DrawerLayout&gt;
  </code></pre>
  
  <p>main activity :</p>
  
  <pre><code> public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
  
  
  
  Toolbar toolbar;
  View root;
  NavigationView nav_draw;
  DrawerLayout drawer_layout;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
      setupToolbar();
  
      drawer_layout = (DrawerLayout)findViewById(R.id.drawer_layout);
      nav_draw = (NavigationView) findViewById(R.id.nav_draw);
      nav_draw.setNavigationItemSelectedListener(this);
  
  getSupportFragmentManager().beginTransaction()
          .replace(R.id.container, new Fragment())
          .commit();
  
  }
  private void setupToolbar(){
      Toolbar toolbar = (Toolbar) findViewById(R.id.tool_bar);
      setSupportActionBar(toolbar);
      getSupportActionBar().setElevation(18);
      final ActionBar ab = getSupportActionBar();
      ab.setHomeAsUpIndicator(R.drawable.abc_ic_ab_back_mtrl_am_alpha);
      ab.setDisplayHomeAsUpEnabled(true);
  }
  }
  </code></pre>
  
  <p>app_bar layout file</p>
  
  <pre><code>&lt;android.support.v7.widget.Toolbar
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:app="http://schemas.android.com/apk/res-auto"
      android:id="@+id/toolbar"
      android:layout_height="?attr/actionBarSize"
      android:layout_width="match_parent"
      android:minHeight="?attr/actionBarSize"
      android:background="?attr/colorPrimary"
      android:elevation="7dp"
      android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
      app:popupTheme="@style/ThemeOverlay.AppCompat.Light" /&gt;
  </code></pre>