I have a Denon MC7000 and there’s a button that is supposed to add a song to the queue (or prepare crate in Serato).  In the midi mapping it says “mark/unmark selected tracks”  Does anyone know what this actually does? it doesn’t seem to do anything

I’m working with an embedded browse where I want the user to be able to mark and unmark records. I have the ‘Row Selector’ turned on. The parent table has 50,000+ records.