Scrollbar overlay not working in 12.10

In gtk3 theme base on Unico engine on Ubuntu 12.10 (Upgrade):

The following use to display a handle on top of my scrollbars. It does not display it since upgrading to 12.10.
.scrollbar.slider.horizontal {
    border-width: 1;
    background-image: -gtk-gradient (linear,
                                     left top, left bottom,
                                     from (shade (@tooltip_bg_color, 1.0)),
                                     to (shade (@tooltip_bg_color, 0.2)));
    -unico-centroid-texture: url("scrollbar_handle.png");
}

Has -unico-centroid-texture: been deprecated, replaced by something else?

I cannot find the documentation...

Thanks.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: gtk3-engines-unico 1.0.2+r139-0ubuntu2
ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5
Uname: Linux 3.5.0-17-generic i686
ApportVersion: 2.6.1-0ubuntu4
Architecture: i386
Date: Sun Oct 21 13:19:23 2012
InstallationMedia: Lubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
MarkForUpload: True
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gtk3-engines-unico
UpgradeStatus: Upgraded to quantal on 2012-10-19 (2 days ago)