The 4.0 Release is all about the Library, and I'd assume they did not want to add anything that distracts from that.

However, now that the good people at Serato have finally realized that a computer mouse actually has TWO buttons on it, I'd say there is a good chance you will get your wish in a future 4.0 update.

I have several remixes and versions of songs that I got from a few Record Pools and would like to preview songs before loading to the deck, I too would like to see this feature implemented in a future release (I’m sure if Rekordbox can do it, Serato can implement this software feature as well).