I should add I was in an emacs without the .emacs customization to allow TAB to cycle the headline visability which explains why I could not do that, but why C-x 5 0 was refused is a puzzle.
> Looking at the file in smerge-mode > and then calling smerge-ediff > produced my Org-Mode buffer > collapsed to > > #+STARTUP: overview > > in all three windows. There was > nothing I could do to expand the > headlines. Then abandoning that, > I found the frame itself wasn’t > willing to be dismissed by C-x 5 0.