message: Used absolute instead of fixed
  Works better with nested tabs like ios twitter example. Not going to suggest nested tabs on web but it is possible if disable the history for all but one tab state navigator
diff: @@ -68,7 +68,7 @@ const styles = StyleSheet.create({
  height: 56,
  flexDirection: 'row',
  alignItems: 'center',
  - position: 'fixed' as any,
  + position: 'absolute',
  width: '100%',
  top: 0,
  left: 0,
  