HorizontalButtonBar does not appear to display disabled buttons with the correct colour backgrounds

While debugging, changing the inactive background to green does not show green buttons. This means the inactive button background is not working.
```swift
static let primaryButtonBackgroundInactive = UIColor { trait in
return colorFrom(trait: trait, lightColor: R.color.mike()!, darkColor: R.color.green()!)
}
```
```swift
static let secondaryButtonBackgroundInactive = UIColor { trait in
return colorFrom(trait: trait, lightColor: R.color.mike()!, darkColor: R.color.green()!)
}
```


Button is disabled but the background image does not appear to be set correctly.