Assigning non-symbol shortcut for switching keyboard layout broken in 13.10

Lost ability to assign Caps Lock or even Ctrl-Shift as a keyboard layout switch.
"Switch to next source using:" field simply does not react on modifier keys combination.
It reacts only if threre is symbol key in combination.
For example:
Ctrl-Shift - does not work
Ctrl-Space - works

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: gnome-control-center 1:3.6.3-0ubuntu39
ProcVersionSignature: Ubuntu 3.11.0-8.15-generic 3.11.1
Uname: Linux 3.11.0-8-generic x86_64
ApportVersion: 2.12.5-0ubuntu1
Architecture: amd64
Date: Sat Sep 28 07:54:28 2013
ExecutablePath: /usr/bin/gnome-control-center
InstallationDate: Installed on 2012-09-08 (384 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Alpha amd64 (20120905.2)
MarkForUpload: True
SourcePackage: gnome-control-center
UpgradeStatus: Upgraded to saucy on 2013-08-10 (48 days ago)
usr_lib_gnome-control-center:
 activity-log-manager 0.9.7-0ubuntu4
 deja-dup 27.3.1-0ubuntu1
 gnome-control-center-datetime 13.10.0+13.10.20130924.2-0ubuntu1
 gnome-control-center-signon 0.1.7~+13.10.20130724.1-0ubuntu1
 gnome-control-center-unity 1.3daily13.06.14.1-0ubuntu1