X2 Studio PRV won't highlight notes introduced from my AlesisQX25 keyboard controller

- I start Sonar as an administrator with my controller plugged in. I select my keyboard as MIDI inputs and controller surfaces input. 
 - Keyboard has individual power supply and its plugged straight in its USB port. It does the same when is running on USB power only. I reinstalled the program with no effect.
 - What is happening is that often there is no sound out of my synth and PRV won't highlight the notes I'm hitting on the keyboard. Usually the sound comes back on after I reset my keyboard (or restart Sonar) and re-check the inputs but the PRV still won't show the notes I'm playing... MIDI meter always shows activity. 
 - Before I had X2 Essential and it did happen that I had this problem but not so often as with Studio.
I feel like there is a compatibility issue between Sonar and my controller ...
What do you think?
 
Thanks..