sudo pacman -S ibus manjaro-asian-input-support-ibus- logout and relogin
manjaro-asian-input-support-ibus simply installs the correct env vars and autostart file via these two files:
/etc/profile.d/input-support.sh
# https://wiki.archlinux.org/index.php/IBus
im=ibus
export GTK_IM_MODULE=$im
export QT_IM_MODULE=$im
export XMODIFIERS=@im=$im
export INPUT_METHOD=$im
export SDL_IM_MODULE=$im
/etc/xdg/autostart/ibus.desktop
[Desktop Entry]
Name=IBus
Type=Application
Exec=ibus-daemon -drx
Terminal=false
Arch Wiki recommends adding --panel=/usr/lib/kimpanel-ibus-panel to make it work also with Input Method Panel widget, I tried it and didn’t seem to work.
I tested it and unicode typing worked perfectly inside Qt apps.