The "Exec" field in /usr/local/share/applications/me.mitya57.ReText.desktop is set to "retext %F". I believe that it should be set to something like "retext.py %F" instead. Otherwise, a user may not start the program from a desktop menu.
I think the right fix would be to create bin/retext It was removed by yuri's change I think.
A commit references this bug: Author: arved Date: Mon Feb 11 21:14:32 UTC 2019 New revision: 492737 URL: https://svnweb.freebsd.org/changeset/ports/492737 Log: Update to a snapshot from master. This should fix the wrong desktop file entry. Add missing dependencies while here PR: 235112 Reported by: 0mp Obtained from: https://github.com/retext-project/retext/issues/425 Changes: head/textproc/retext/Makefile head/textproc/retext/distinfo head/textproc/retext/files/
Thanks for your report. The issue should be fixed now.