What is this link/part of the Now-Playing panel?

[Skoop]

I have the Now-Playing panel situated in the lower part of the left sidebar.  Some text strings for various of the fields display info on the album.  Right above where that displays, however, is the link indicated by the arrow.  It is clickable and alternates being "Playing Track" and "Selected Tracks".  Clicking them, though, doesn't appear to do anything.  The actual playing track info scrolls in the player bar at bottom of the main panel. 

I don't think I ever noticed this until just recently, and my configuration has been unchanged for years.  Sheesh. 

Enlighten me, if you would.  Edit:  version 2.5.whateverwasthelastfix

[Pingaware]

The details shown there will change if your selected track is different to the playing track.

[Skoop]

Hmmm, that apparently only works if the track details are displayed in the NP panel, instead of scrolling on the player bar. 

[Pingaware]

Yes, it only changes the Now Playing panel, not the player bar.