It used to be that when I opened a new mp3 file from a folder, iTunes highlighted that file as it played. If I decided I didn’t want it in my library after listening to it for a few minutes (or three seconds), I could just switch back to that screen and quickly delete the entry from my iTunes library.
A few (?) versions ago, Apple updated the software with some new features and somehow dropped this very intuitive, useful feature that I believe always existed in the software since the first version. Why?