well,
press a pad with sample and go to TRACK mUTE
...that's it
sample or loop is playing until you press same pad again
well it was some older version of JJ OS...maybe it is not working anymore... need to check
PS I remember version of JJ OS that you could run sequence and preview samples at same time....it was bit tricky as well, you need to have a foot controller, though. go to load screen, preview samples and press footcontroler ( start/stop) - and here we go:0 you could play sequence and preview samples...
then next ver of OS wasn't working so good with this option, now it has gone baby gone...