I was getting recently a lot random crashes with xfce4-xkb-plugin. Also when I opened the plugin properties the greek layout variant text was all scrambled and ineligible. Having searched through the internet and bug trackers I couldn’t find something similar so I started suspecting that my setup was broken. A look in /usr/share/X11/xkb/rules/xorg.lst showed me that the greek layout was ‘gr’ and not ‘el’ as I had specified it.
You can get the greek layout code with:
grep -i 'greece' /usr/share/X11/xkb/rules/xorg.lst
and the keyboard variants with:
grep 'gr:' /usr/share/X11/xkb/rules/xorg.lst
so this is how my (correct) keyboard settings look:
Section "InputClass" Identifier "Keyboard Defaults" MatchIsKeyboard "yes" Option "XkbLayout" "us, gr" Option "XkbVariant" ",extended" Option "XkbOptions" "grp:alt_shift_toggle, terminate:ctrl_alt_bksp, lv3:ralt_switch_multikey, eurosign:e" EndSection
(The lv3 multikey option is used to type ligatures see: http://shtrom.ssji.net/skb/xorg-ligatures.html)