I'm getting the typical error "The function evaluation requires all threads to run." but I don't have the little button that is usually there to do as it suggests -- i.e. run all the threads, as described here.
And yes, I do have this set:
Comments at the link above indicate this feature may have been removed in VS 2015, but I just used it recently in VS 2017 and today is the first time I've noticed it missing. I restarted VS, no change.