When using tabBarPosition: top in Router Flux, the activeBackgroundColor
and inactiveBackgroundColor properties are not applied.
In React Navigation the properties are applied when in both positions.
You can run both of the apps included in this repo, changing the
tabBarPosition in each to see how the activeBackgroundColor behaves.
The only file changed from a default react-native init installation in the
App.js which contains the demonstration.