Title says it.  In the manual, it shows a power button to activate the sound source....it's in the upper left of the picture of the percussion item... (IN THE MANUAL).   I can record midi, etc.  And when I 'mouse" the sound...it comes out...but I can't activate it to have midi play it except from the song block area

infact, instead of the percussion pads "grey'd out" (like the pic in the manual), they're always active and only have the drop down arrow for the percussion menu.

nevermind... you go into "play edit mode"