I want to change the velocity of all occurrence of a specific note, for example limit the maximum velocity of note C3 to 100.  In the past, in PRV I can select the note and right click (to bring up a menu, Sonar 8.5, I think) or go to the Process menu and select the MIDI Effects and bring up the Velocity tool (Sonar Platinum).
Don't know when it got changed but not the MIDI Effects is greyed out.
The only thing I can do now is insert the Velocity tool as plugin in the track's FX bin.  This however would impact all notes of that track and not just the one note.
 

I know you can change the RELATIVE velocity of the note in PRV by highlighting it in the left-hand pane and then manually dragging the velocity in the bottom pane.
For what you want, i'd clone the MIDI track, delete C3 from the first track and delete everything except C3 in the other.  Then process the entire 2nd MIDI track to force a 100 velocity (i think it's in the Process tab, but i'm not at my DAW to confirm).  Then drag the C3 MIDI track back up into the main track.
There's probably an easier way, but this is my workflow.

https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=EditingMIDI.15.html
 

 
Pretty easy. Use the smart tool 

Cactus Music
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=EditingMIDI.15.html
 

 
Pretty easy. Use the smart tool 

Thanks for responding but that's not what I was asking.  Basically I'm looking for a way to use the MIDI Velocity tool/plugin but apply it to any selected notes and not the entire track.  I've done this in Sonar many times but apparently something changed somewhere along the way.

Sorry I don't understand why anyone would work that way? That involves a lot of mouse clicks and opening menus.
 
I make hundreds of velocity changes on my projects daily. It's an important tool to make interesting tracks. The timber of many sound changes at different velocities. Even a snare drum needs just the right place to get the tone right  and rolls need to be just so. I would never go back to the old way.
 
The smart tool makes this a one click and drag move, you can even group notes or highlight the whole track and move them up and down. If you want a part. like bass to be all the same velocity you highlight the whole track and drag the velocity to max, let go, now drag it down to the sweet spot, I like to make all my bass part even at 100. 
So is it you have not figured the smart tool out or ?? please explain. 
 
 

@Cactus Music. 
Yes I use Smart Tool and can do all that you said. But I do not want all notes to be the same velocity, and if I group or selected a bunch of notes and drag up/down, they all move at a relative level. 
Try this example, let say if a note velo is 5 and another is 10, moving them up by 1 means now you have a note at 6 and the other now at 11.  What I want to do is limit the higher velocity to, say 9, mean one note remains at 5 and the other reduces to 9. 
 

Yes, Velocity scaling will do that, but then what I do is this. 
 
say my notes are ranging from 80 to 127,, I want to raise the 78 up to 90 and lower the 127 as well. 
so there will be less difference from hi to lowest when I'm done.  
Highlight all then grab a note that is 80 and raise it to 110 ( + 30 )  let go 
Now grab the same note that was 80 originally and pull it from 110 down to 90.  -20
The notes that were 127 will pull down to 107. 
all the notes that were below 97 will range from 97 - 107 
all the notes that were above 97 will now be 107. 
 
but now you still need to figure out why you tools are grayed out. 
I just tried it and it works for me
I used the "select" tool, highlighted a group of notes, right click and the dialog opens with all the editing tools

Where's my post gone?
 
It was there, I went in and edited it, now it's gone completely
 
At the risk of repeating myself, you have 2 other options.
 
Use Process > Find/Change or, use the Transform Tool
 
https://www.cakewalk.com/Documentation?product=SONAR&language=3&help=EditingMIDI.25.html
 

Cactus Music
I just tried it and it works for me
I used the "select" tool, highlighted a group of notes, right click and the dialog opens with all the editing tools

That's it, it does work, use the "Select" tool and not the "Smart" tool.  When you use the Smart tool and right click, it un-selected all the notes and since there is no note selected, the tools are greyed out.
 
btw I tried the method you mentioned with Smart tool but that's a lot of mental math for me and I got lost remember which note to grab.
thanks

I was a carpenter for a long time, you get good at math :)
The Smart tool can also lasso notes. I just figured this out while helping you, duh...I've always used the select tool. 
point on the background, now LEFT click and hold and drag to lasso and highlight. Now right click to select action.