After intallation I have to update icon cache manually as desktop icon was not displayed. INSTALLS_ICONS= yes is needed as described in https://www.freebsd.org/doc/en/books/porters-handbook/using-gnome.html
A commit references this bug: Author: fjoe Date: Tue Oct 4 10:58:09 UTC 2016 New revision: 423251 URL: https://svnweb.freebsd.org/changeset/ports/423251 Log: - Use INSTALLS_ICONS=yes - Bump PORTREVISION PR: 213024 Changes: head/databases/pgadmin3/Makefile