I haven't used my DAW a whole lot since I moved house a couple of months ago.  I caught up on all the Sonar Platinum updates and also updated Melodyne to the latest version last night.
 
I don't know if this is new, or a result of the latest Sonar/Melodyne updates, but if I create a new FX Region for Melodyne, or simply open the Melodyne editor for an existing region and then un-dock the Melodyne window (I have full Melodyne Editor, by the way), all the notes disappear in Melodyne and I can't edit anything, as I can't see anything.  Re-docking the window seems to sort it out.
 
Is this a new bug, or is it just me?  Can anyone else confirm?

I know the answer to this but I'm not at my DAW so my explanation might be a little off.   In my edit window (latest Melodyne Studio) there are 2 colored buttons (icons look similar to the notes in the window) next to a button with a wrench icon in the left middle of the upper tool bar (just left of the select arrow). Try clicking/toggling on the one that isn't selected and see if your notes reappear.
 
This relates to whether you are working in "clip mode" or "track mode."  See here: 
 
http://helpcenter.celemony.com/hc2-content/melodynestudio4/en/m4tour_workingwithara.html?edition=melodyne-studio&docTypes=anleitung~tutorials~tipps-info&lang=en&sort=RELEVANCE&grouped=false&query=clip%20mode&showStartPage=false
 
If this doesn't make sense with your view configuration, message me and I will look at my set-up later tonight and try to describe it better.  (I'm in Hawaii so that may be midnight or later where you are).
 
Aloha,
Bill