title: Android Navigation Component fragment transitions have white background
body: <p>I'm using the Jetpack Navigation library and having an issue with the fragment transitions, either if it's a fade or slide animation it always has a white background instead of the previous screen content.</p>
  
  <p>fragment A -> fragment B, when the animation is running instead of seeing the background as fragment A, it's a white background.</p>
  
  <p><em>navigation</em></p>
  
  <pre><code>  &lt;fragment
        android:id="@+id/nav_page"
        android:name="my.fragmenta"
        tools:layout="@layout/fragment_a"&gt;
  
      &lt;action
          android:id="@+id/action_to_b"
          app:destination="@id/nav_b"
          app:enterAnim="@anim/slide_in_up"
          app:popExitAnim="@anim/slide_out_down"/&gt;
    &lt;/fragment&gt;
  </code></pre>
  
  <p><em>activity style</em></p>
  
  <pre><code>  &lt;style name="AppTheme.NoActionBar"&gt;
      &lt;item name="windowActionBar"&gt;false&lt;/item&gt;
      &lt;item name="windowNoTitle"&gt;true&lt;/item&gt;
      &lt;item name="android:statusBarColor"&gt;@color/statusBarColor&lt;/item&gt;
    &lt;/style&gt;
  </code></pre>
  
  <p><em>anim files</em></p>
  
  <pre><code>&lt;translate
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:fromYDelta="100%p"
      android:toYDelta="0"
      android:duration="@android:integer/config_longAnimTime" /&gt;
  </code></pre>
  
  <p>and</p>
  
  <pre><code>&lt;translate
      xmlns:android="http://schemas.android.com/apk/res/android"
      android:fromYDelta="0"
      android:toYDelta="100%p"
      android:duration="@android:integer/config_longAnimTime" /&gt;
  </code></pre>
  
  <p>Anyone has an idea how to fix it? </p>