X DJ-RX - How do i know which track's ive alreadt played ?

There lighter colored then the others.

thanks. And do they go back to normal colour when u turn it off and on or ? - can u choose if they stay light ?

There's now why to turn it on or off manual, so yes, if you turn the console off - on they are reset. But remember: only the track played within the playlist is checked as played. If you have the same track in an other playlist it is not marked as played in that list. (To bad!!)

OK, so if your playing from your whole collection ? they dont get highlighted ??
Or if i make a playlist that mirrors my recordbox collection, that will work ?

I only use playlists

If you have the same song, in two different playlists (A and B), and you play that song from playlist B, it will go grey in that playlist, but the same song in playlist A will remain 'unplayed'.

Jep, that's how it works. Should be in all playlists, hope the fix that.