iTunes: Double clicking one song plays others

I've had Mac since 1986 and when I double click on anything, it simply opens that thing. In iTunes, it plays that song...This has been consistent with computers for decades, so why, now that I upgraded to Mojave, does double-clicking on the song I choose result in the playback of a song I did not choose? Each time I double-click on the same song it plays another one of my other songs, flying through my library as rapidly as I can double click on that one song, as I watch each one change, artwork and all, in the display window?

Never fails...Just when the software works, Apple complicates it. Still mourning over the death of the old Preview.