title: Icons not showing up in bottom tab navigator
body: <p>Creating a bottom tab navigator and for some reason the Icons don't show up. The Icons show up when I use it outside of the bottom tab navigator. I looked through many stack overflow solutions and I implemented all of them but for some reason it still isn't working!</p>
  
  <pre><code>const tabNavigator = createBottomTabNavigator(
    {
    Home: {
      screen: EventNavigator, 
    defaultNavigationOptions: {
      tabBarLabel: 'Home',
      tabBarIcon : ({tintColor}) =&gt; (
        &lt;Ionicons name='ios-home' size={30} color={tintColor}/&gt;
      )
    },
  },
    Categories: {
      screen: CategoryNavigator,
    defaultNavigationOptions: {
      tabBarLabel: 'Categories',
      tabBarIcon: ({tintColor}) =&gt; (
        &lt;Ionicons name='ios-search' size={30} color={tintColor} /&gt;
      )
    },
    },
    Favourite: {
      screen: FavouriteNavigator,
      defaultNavigationOptions: {
        tabBarLabel: 'Favourite',
        tabBarIcon: ({tintColor}) =&gt; (
          &lt;Ionicons name='ios-heart' size={30} color={tintColor}/&gt;
        ),
      }
    },
  },
  {
    order: ['Home', 'Categories', 'Favourite'],
    tabBarOptions: {
      showIcon: true,
      activeTintColor: "#00ACF0",
      inactiveTintColor: 'gray',
      style: {
        backgroundColor: '#fff'
      },
    }
  }
  )
  </code></pre>