After starting to upgrade to gnome-3.20 gnome-terminal disappeared from my gnome favorites. I tried to readd. I do not get any error. But it did not enter in the favorites. root@lynx:/root(6)# qlist -Iv gnome | grep 3.20 games-arcade/gnome-nibbles-3.20.1 games-arcade/gnome-robots-3.20.2 games-board/gnome-chess-3.20.1 games-board/gnome-mahjongg-3.20.0 games-board/gnome-mines-3.20.0 games-puzzle/gnome-klotski-3.20.2 games-puzzle/gnome-sudoku-3.20.2 games-puzzle/gnome-taquin-3.20.2 games-puzzle/gnome-tetravex-3.20.0 gnome-base/dconf-editor-3.20.2 gnome-base/gdm-3.20.1 gnome-base/gnome-control-center-3.20.1 gnome-base/gnome-desktop-3.20.2 gnome-base/gnome-keyring-3.20.0 gnome-base/gnome-session-3.20.1 gnome-base/gnome-settings-daemon-3.20.1 gnome-base/gnome-shell-3.20.2-r1 gnome-base/gsettings-desktop-schemas-3.20.0 gnome-base/nautilus-3.20.1 gnome-extra/gnome-calculator-3.20.1 gnome-extra/gnome-calendar-3.20.2 gnome-extra/gnome-characters-3.20.1 gnome-extra/gnome-clocks-3.20.1 gnome-extra/gnome-contacts-3.20.0 gnome-extra/gnome-documents-3.20.0 gnome-extra/gnome-power-manager-3.20.0 gnome-extra/gnome-shell-extensions-3.20.1 gnome-extra/gnome-shell-frippery-3.20.0 gnome-extra/gnome-system-monitor-3.20.1 gnome-extra/gnome-tweak-tool-3.20.1 gnome-extra/gnome-user-docs-3.20.2 gnome-extra/gnome-weather-3.20.1 gnome-extra/sushi-3.20.0 x11-themes/gnome-themes-standard-3.20.2 root@lynx:/root(7)# qlist -Iv gnome-terminal x11-terms/gnome-terminal-3.18.3
The issue disappeared with the upgrade to gnome-terminal-3.20.2.