Hmmm, maybe I just stumbled on the answer myself in the "groff(7)" manual page.
That page says that the only TABs that can appear on a "control line" must come between the leading period in the first column, and the command. So, I presume that my putting a TAB on a "mom" macro line *after* the macro name (and its arguments as well) is not correct. Please let me know if I'm missing anything. Otherwise, sorry for the noise on the mailing list. -- Steve Ross On Saturday, February 20, 2021, 9:15:32 PM CST, Steve Ross via <groff@gnu.org> wrote: Hi, A question on the "mom" macro set (version "mom-2.4-4_e") with "groff" 1.22.4 with regard to the TAB character... I have attached four files. - "correct-author-name.mom" -- a six-line "mom" file. This file correctly produces "correct-author-name.pdf". - "correct-author-name.pdf" -- The PDF output of "mom" and "groff". - "issue-author-name.mom" -- This file is identical to the first ".mom" file, except that I appended a TAB character to the end of the ".AUTHOR_COLOR coral" line. - "issue-author-name.pdf" -- The incorrect PDF output that features an unexpected right square brace and the author's name in the color black instead of the color coral. Why does the TAB character have the unexpected effect?Should I avoid using TABs in favor of spaces?(I inserted the TAB for the purpose of moving to the right of the text AUTHOR_COLOR to add a comment to the end of the line.) Thanks in advance for any help,-- Steve Ross