OK, chalk this up to a brain spasm, or maybe the fact that the temperatures here in Chad are about 45-50C... That option is still there, and I can open Changes.txt as always...
But to be fair... Look at the last 4 checkboxes in the screenshot above. The file that is to be edited is in parentheses at the end of the checkbox text. In the one with Changes.txt, that filename is NOT in the parentheses, but PrintDraftChanges.txt is! I knew that I didn't want to change PrintDraftChanges.txt, but rather the changes.txt, so I was looking for that filename in parentheses! Maybe the text of that checkbox should be changed to:
"Apply changes (changes.txt and PrintDraftChanges.txt)"