I used to be able to listen to midi while I played over the top of what was there. Now I can't (upgraded to X3) ... should I record on top of midi already there, the underlying track auto mutes ... and then stays muted.
 
I do not like this Sam I am.
 
How do I fix it?
 
... and thanks! :)

Click and hold the record button and choose "Sound on Sound." X3 defaults to the new Comping mode.

Muchas muchas muchas gracias!!!

Really.

Still learning ... slowly. :)