IMO, this function should be called `setPlayButtonAndSeparatorVisibility()` or as the API was before `hidePlayButtonAndSeparator()` and `showPlayButtonAndSeparator()` (readability is probably subjective at this point) to better reflect what this function is doing, since it's not side effect free (it also hides the separator, not just the button).

As we do not have documentation in the form of a JavaDoc, we should either use telling names (sometimes resulting in overly verbose method names) or at least document the functionality in a test, since the tests are executable documentation. Maybe I've overlooked something, but from what I've seen, there is no `assertX()` about the separator being hidden or shown.