In Ubuntu 13.10 and older there were a keyboard layout option "use keyboard led to show alternative layout", so I could use it to have caps lock LED indicating current keyboard layout. Now there is no keyboard layout preferences. I tried to use gnome-tweak-tool, but there is no that option too. Also I tried to type in console:
setxkbmap 'us,ru' -option 'grp:ctrl_shift_toggle,grp_led:caps,compose:menu'
and add
XKBOPTIONS="grp:alt_shift_toggle,grp_led:caps"
to /etc/default/keyboard
, but this doesn't work too.