I use Ubuntu 18.04 Mate Edition with installed Unity. I've got several keyboard layouts and they're switching nice in Mate, but when I try to do it in Unity (upd: by shortcut) nothing happens. I've configure both Mate and Unity settings.
ptrknvk@stiven:~$ cat /etc/default/keyboard # KEYBOARD CONFIGURATION FILE # Consult the keyboard(5) manual page. XKBMODEL="pc105" XKBLAYOUT="us" XKBVARIANT="" XKBOPTIONS="" BACKSPACE="guess" ptrknvk@stiven:~$ gsettings get org.gnome.desktop.input-sources xkb-options @as