Margins

[Mike Kenyon]

Does anybody know which package needs to be installed to get
the "margins" option to appear in the XFce Settings Manager?
So far I've installed the following:

libxfce4util
libxfcegui4
libxfce4mcs
xfce-mcs-manager
xfce-mcs-plugins
gtk-xfce-engine-2
xfcalendar
xfce-utils
xfce4-iconbox
xfce4-panel
xfce4-modules
xffm-4.0.3
xfce4-mixer-4.0.3
xfce4-systray-4.0.3
xfce4-themes
xfce4-toys
xfce4-trigger-launcher
xfdesktop-4.0.3
xffm-icons-4.0.3
xfprint
xfwm4
xfwm4-themes

Thanks in advance.
Mike.