fcitx on debian 11 missing tray icon solution:

This is because Debian 11 with Gnome does not ship with the packages to display tray icons. To install and enable the correct packages to display tray icons, run the following command:

sudo apt install gnome-shell-extension-appindicator

Then either reboot or log out and back in to Gnome, and run the following command:

gnome-extensions enable [email protected]