The Apple Mac people have consistently managed to make each version of iTunes slightly less useful than the last. With 12.01.26 they have ditched the sidebar completely which means that you can no longer drag songs from the library to playlists and between playlists. To do this now requires a lot more work and having to switch pages.
There appears to be a syndrome common among software developers which I shall call the "mend it even though it's not broken" syndrome. They are paid to do something and obviously fear losing their jobs if they don't do something. So they will change things even if they don't need changing just to kid themselves and their employers that they are still worth employing.
This would not be so bad if the software companies were not so arrogant and would put things back to how they were when people complained about the new stuff. But software developers are like composers who compose unlistenable crap and who then accuse the audience of being wrong when the audience tell them it's shit.