title: Drawable icons aren't displayed on Button
body: <p>Everytime I try to add some drawable icons to a button they are not displayed even if it's a button or a Material Button </p>
  
  <pre><code>   &lt;Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                      android:text="Person"
                    android:drawableStart="@drawable/ic_person_pin_circle_black_24dp"
                    /&gt;
                &lt;Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_gravity="center"
                    android:text="Package"
                    android:layout_marginStart="10dp"
                    android:drawableStart="@drawable/ic_business_center_black_24dp"
                    /&gt;
  
  
  
  </code></pre>
  
  <p>In the left I have the "pin person" icon and the "briefcase " icon, but on the layout aren't display. Do you know what might cause this?</p>