title: React Native Router Flux Tab Navigation does not show Tab Icon for one specific component
body: <p>I've got a problem with react native router flux navigation. I want to display an icon for my tabs with react-native-vector-icons but for the component {ScreenOverview} it doesn't show the icon.</p>
  
  <p>Code:</p>
  
  <pre><code>const Scenes = Actions.create(
  &lt;Router&gt;
      &lt;Scene key='root' hideNavBar&gt;
  
          &lt;Scene
              key='amount'
              component={ScreenAmountPlayer}
              title='AmountOfPlayer'
              initial
          /&gt;
  
          &lt;Scene
              key='names'
              component={ScreenEnterPlayerNames}
              title='EnterNames'
              hideNavBar
          /&gt;
  
          &lt;Scene
              key='playScreen'
              hideNavBar
              tabs={true}
          &gt;
  
              &lt;Scene
                  key='Play!'
                  component={PlayScreen}
                  icon={TabIcon}
                  iconName={'play-circle-o'}
                  hideNavBar
              /&gt;
  
              &lt;Scene
                  key='Overview'
                  iconName={'list-ul'}
                  icon={TabIcon}
                  component={ScreenOverview}
                  hideNavBar
              /&gt;
  
          &lt;/Scene&gt;
  
      &lt;/Scene&gt;
  &lt;/Router&gt;
  ) 
  </code></pre>
  
  <p>With this code it looks like that:
  <a href="https://i.stack.imgur.com/3pePI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3pePI.png" alt="enter image description here"></a></p>
  
  <p>When I change the second scene to:</p>
  
  <pre><code>&lt;Scene
      key='Overview'
      iconName={'list-ul'}
      icon={TabIcon}
      component={PlayScreen}
      hideNavBar
  /&gt;
  </code></pre>
  
  <p>It looks like that: 
  <a href="https://i.stack.imgur.com/FxBoF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FxBoF.png" alt="enter image description here"></a></p>