Changing keyboard layout does not work

Changing keyboard layout does not work in Gnome Fallback. The language indicators aren't even present. The issue was introduced with Trisquel 7.0 and reported many times in the forum. However there was a workaround installing ibus until recently. The workaround does not work now, after updating to ibus 1.5.5 - with shortcuts and clicking with the mouse on the ibus icon in the panel.

The issue in not present in Gnome Shell - tested it myself, reported in the forum as well. If I change the layout in Shell session and switch to Fallback the layout stays the changed one.

Seems pretty critical bug to me since a major feature of the OS is missing actually for all the people who need more inputs and like the Fallback experience.