title: Error using stackNavigator + tabBar - React Navigation4
body: <p>After updating react-navigation to version 4. I can't run the project. Using the navigations. Displays this error. Sometimes the app goes all white. 
  The complete project is available on git hub: <a href="https://github.com/brunowbbs/React_Navigation4" rel="nofollow noreferrer">https://github.com/brunowbbs/React_Navigation4</a></p>
  
  <pre><code>//Stack
  import {createStackNavigator} from 'react-navigation-stack';
  
  import Screen1 from './Screen1';
  
  const telas = createStackNavigator({
    Tela1:{
      screen:Screen1
    }
  })
  
  export default telas(telas);
  
  
  //Tab
  
   import {createAppContainer} from 'react-navigation';
   import {createBottomTabNavigator} from 'react-navigation-tabs';
  
  import Tela1 from './Tab1';
  import Tela2 from './Tab2';
  
  
  const telas = createBottomTabNavigator({
    Tela1:{
      screen:Tela1
    },
    Tela2:{
      screen:Tela2
    }
  })
  
  export default createAppContainer(telas);
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/9xvxz.png" rel="nofollow noreferrer">Error image</a></p>