question about highlight system in 'album covers' view

[chrctrlmt]

I have a question about the 'show highlighting' option when in 'album covers' view.  I use the application-wide highlighting system, but this seems to be separate from that.  How is this used?  The screenshot shows the application-wide system found in preferences, and the separate highlighting system found in configure layout>main panel>customise panel.  I have highlighting rules set, but when I select 'define rules' under the customise panel for album covers, no rules are defined.

[chrctrlmt]

Disregard - I discovered this is a separate highlighting system for the album covers themselves, and not for the tracks contained within.