Bug#402433: postinst: ETOOMUCHCRACK
Previous postinstall was removed already but the "$conf_report_setup" doesn't fly either in case you were planning on leaving that in your next release. That is what popcon is for.
Bug#331707: gnome-session: missing icons on second session
2.12 did not include the patch you referenced. Or if it did the patch didn't resolve the problem of same user in two xsessions missing icons and also missing mouse controls in the second xsession. apt-cache show gnome-control-center Package: gnome-control-center Priority: optional Section: gno