xkeyboard-config-2.18-alt1 /usr/share/X11/xkb/symbols/shift has the following rules which doesn't seem to make the right shift ineffective: // Toggle CapsLock when pressed together with the other Shift key. partial modifier_keys xkb_symbols "rshift_both_capslock" { key <RTSH> { type[Group1]="TWO_LEVEL", symbols[Group1] = [ Shift_R, Caps_Lock ] }; }; but they do. Shift+Shift toggle CapsLock, but a single right shift doesn't act as shift modifier. $ cat /etc/X11/xinit/Xkbmap -layout us,ru -option grp:shift_caps_switch,shift:rshift_both_capslock Perhaps, a related bug/discussion: https://bugzilla.altlinux.org/show_bug.cgi?id=32655 (the common thing is that the behavior of pressing both right and left keys is used)