In the Nightly dated 30-May: I put song 1 and 2 in the queue, song 1 playing. I flick away song 1. Song 2 starts playing. The "Track: ... Progress:" pop-up is still displayed—but it's got no text! It's just a square above the line graph.
PS—This seems to be the case whenever the queue has only one entry. Someone satisfied my request that multitrack progress not be displayed when there's only one track, thanks! But the pop-up should disappear entirely.