This seems to have popped up just today.  Normally I drag Melodyne into the effects bin and transfer.  Before today, I could double click the left mouse button and it would play back what's been transferred.  It stopped doing it today...for some reason I haven't yet figured out.  I can hit the spacebar and Sonar plays but if I want to solo what's in the Melodyne plugin I'm not able to do it.  Anyone have any suggestions?  (I Googled the issue but found nothing... may not be using the right terms...)