Was the Midi Note On Indicator function in the Piano Roll removed in X2a ?  Worked fine in X2.  To explain further I'm referring the the keys lighting up on the vertical keyboard in the Piano Roll when incoming midi notes are received. I've looked for options to turn this function on but found none. Thanks.

I do not believe it was removed. I just opened the PRV and could see the PRV keyboard change when I pressed keys on my controller. Running X2a Producer 64bit on Win7 Home Premium.

Well what the heck then....I've got the same specs as you. Do you have more than one controller hooked up ? USB or actual Midi In ? Can't see any reason it wouldn't work as all the controllers work on my Axiom.  Hmmm let me try it again........

Is the Aim Assist on?

Hang on I'll check.  I just tried it again and the notes from my Axiom do not show but the notes from my Trigger Finger do.  Gotta be some setting......I'll be right back....
 
Same result with Aim Assist on or off.  Axiom notes do not show in the Piano Roll but are recorded as expected. Trigger finger notes do show in the PR......weird.
 

When I tested only the keyboard controller (Alesis Q49) was on. It is currently on a USB port. I have a pad controller that uses a standard MIDI input on my audio interface but it was turned off at the time.

Ok got it......I had to disable my Trigger Finger then close down Sonar.  I then reopened it and reselected the Trigger Finger and now both controller's incoming midi notes show in the PR. Strange little ghost in the machine.  Thanks for the help guys!

Glad you found out the cause. I had exactly the same problem when I installed X2a, the highlight disappeared. I clean re-installed X2 and made sure the highlight was there, and then re-installed X2a, which made the highlight disappear again. I contacted tech support but they had no idea what was causing the problem, so I gave up. Then a month or two later, I just noticed the highlight was displayed there all right. I only use one MIDI keyboard and I still don't know what I did to get the highlight back.
I wasn't sure if the Aim Assist had something to do with it (someone suggested it when I had the problem), but now I'm at the daw and it obviously has nothing to do with the highlight.