The keyboard layouts plugin which I use on XFCE to switch between layouts (like the name says) stopped working on the Update to XFCE 4.10.1. The reason is, that "Keyboard Layouts" depends that xkbcomp is available in /usr/share/X11/xkb. To fix this, simply make a symbolic link:sudo ln -s /usr/bin/xkbcomp /usr/share/X11/xkb/That's it.
I have asked a related question in different sites such as here in German and a related thread here, a different case in the latter though.
I almost solved the question here, basically: "/etc/default/keyboard" -modification and one-line "$ setxkbmap -option grp:caps_toggle -variant dvorak-intl,nodeadkeys, us,de,no &" -- but the layout-settings get reseted after reboot.