I think it absolutely makes non sense alternating "lyrics" and "behind the lyrics" in the same field. We have two great features that could add to the user's experience but in the moment that you decide to alternate from one to the other constantly both features become useless. That's a pity i think. You either want to read about the history and facts behind the lyrics without being interrupted by the lyrics itself, or you want to sing/read along so switching to "behind the lyrics" actually becomes a huge annoyance. The combination of both doesn't make any sense i can think of, i can't imagine a user trying to do both at the same time. I hear the feature to turn off "behind the lyrics" was removed, in case this was done without users voting for it i suggest taking into consideration doing the same for this case, as part of the same move. That way at the end of the day you did improve the user experience instead of getting rid of a useful feature.