Here is one more tweak I added to my highlighting settings.Problem
After setting up different colors for both playing album and playing track, they are now easy to discern.
But when playing track is selected, it's not easy to find out which track is playing track. You have to look hard for the small speaker icon.Solution
Set up another rule for playing track:
album is [playing track]
title is [playing track]
Playing track is now standing out even when it is selected.
This is how it looks when another track is selected.
Note that playing track's light-green-color highlight bar is set by highlighting settings, whereas its cyan-color text is set by Now Playing settings.