Input method needs to be manually added to have a usable system.

 * GNOME shell: Settings -> Keyboard -> Input Sources -> +
 * ibus-setup: Input Method -> Add

Keyboard mode switching is SUPER-space for GNOME3.

Please read following 2 files before filing a bug report:

 * /usr/share/doc/ibus/README.Debian
 * /usr/share/doc/im-config/README.Debian.gz

