Once again, I have no idea what's going on...
 
I have a midi track.  I view it in PRV.  I have the Smart tool selected.  I hover over the front edge of a note to move the start.  Instead of moving the note, I get another note added.  This was not immediately obvious, as the new note overlays the existing note.  But I noticed I was getting multiple velocity lines at the start of edited notes.  So I move/dragged the note and found another note under it.
 
I've used PRV before and had no problems.  I must have some settings muffed up.  But I have no idea where to look.
 
Ideas?  Thanks
Keith
 

Are you sure your track didn't already have duplicate notes to begin with? Or maybe you have more than one track showing in the PRV with the same clip in it? Did you start with a recorded clip, or was it drawn from the start? Is there more than one lane in the track? Check the Event List for duplicate notes (same start time and duration), possibly on a different channel.

There is a track list in PRV. Make sure you have the right track enabled for editing. You might only have it visible now and so when you click you are actually editing a different take or track.

Also, if you are actually drawing new notes, it might be that you're trying to grab the note closer to the start than you should. If the notes are very short, you might need to zoom the timeline a little.

Thanks for the posts.
 
I don't know how it happened but my midi clip started off with two copies of every note.  I found this out when I went through the clip deleting duplicate notes.  So every time I would move the start of a note I'd see two velocities.  Looking at the Event List I could see the duplicates.  I couldn't find an easy way to delete the duplicates so I went though every note, right clicking to delete one copy.  PITA.
 
PRV only had one track loaded.  It contained one clip.  The clip was copied from a comp take lane of another track.  So somewhere the notes were duplicated.  (I'm guessing during the second comp flattening process, but I really don't know...)
 
Keith
 

I think I figured out what the problem is since the same thing just happened to me.  Luckily I was able to figure out the problem.  
 
When you have multiple take lanes but you don't have one selected via the comping tool as the "active" take, the piano roll will show all of the notes for all of the takes.  Since you had copied a track it was two sets of the same data in this case.  
 
Try this:
1) Open the clip in the piano roll like you did before and notice the two takes 
2) Now go and select one of the takes as the active take with the comping tool.  Piano roll should now correctly display just the info for one take.
3) Once you've selected an active take, the only way to get it to display the bad behavior is if you hold control and select more than one take as the "active take" with the comping tool.

As a follow-up note that regardless of which take you double-click to edit, the piano roll will only display the actively selected take.  
 
The whole thing doesn't seem particularly intuitive, but maybe it's to prevent accidentally editing the wrong take or something.
 

Paste seems to be a perpetual problem in sonar -- is it possible you pasted twice, since often a paste is nearly invisible until you use 'bounce to clips' to eliminate overlapping midi clips?  
 
Another faint possibility is a keyboard with the control key stuck on -- then every click to adjust a note ends up a duplication of a note.