I'm running Ubuntu 15.04 with xdm as the display manager, and a custom multi-monitor and keyboard setup defined in xorg.conf.
xdm picks up the keyboard config correctly, setting the layout to "gb", and with the caps and ctrl keys swapped.
However, when I start Window Maker, or any other display manager, I find that my keyboard layout reverts to US. The ctrl/caps keys stay swapped though.
xorg.conf:
Section "Monitor"
Identifier "DP1"
EndSection
Section "Monitor"
Identifier "HDMI2"
Option "LeftOf" "DP1"
Option "Rotate" "left"
EndSection
Section "Device"
Identifier "intel"
Driver "intel"
# Option "TearFree" "true"
Option "Monitor-DP1" "DP1"
Option "Monitor-HDMI2" "HDMI2"
EndSection
Section "InputClass"
Identifier "caps as ctrl sun gb keyboard"
Driver "evdev"
MatchIsKeyboard "yes"
Option "XkbLayout" "gb"
Option "XkbModel" "sun_type7_usb"
Option "XkbRules" "xorg"
Option "XkbOptions" "ctrl:swapcaps"
EndSection