I've traced it down to font selection. When I change the font to a larger size (Monaco or Menlo) then the top of the contents of the frame is off the screen, "a

I've traced it down to font selection. When I change the font to a larger size (Monaco or Menlo) then the top of the contents of the frame is off the screen, "above" the Mac menu bar. Strangely, Courier New works correctly with larger font sizes. I tried the suggestion elsewhere on this page about setting font and fontset together, but that didn't fix the problem.