I am using iMac 10.14.6 and Studio One 4.6.2 and am unable to add an instrument track in a song as the two individual tracks then play together eg a pad from Presence and a piano from Arturia - will sound very nice together but I want to hear the individual sounds on the individual tracks before recording - I recently watched one of Gregor's videos about layering multi instruments and wonder whether I have /have not ticked a box or done something since which is upsetting the tracks - I use a Yamaha PSR -E413 keyboard..could it originate here, if so can it be fixed.....it is very frustrating..thanks for your time.