For god-knows-what reason, at-spi is trying various formats
of strings when registering listeners, triggering an ugly
(gnome-shell:4411): Clutter-WARNING **: invalid object type create
warning in .xsession-errors. Stop doing that.
Also don't leak temporary string arrays that are a side-effect
of passing parameters around as formatted strings.
https://bugzilla.gnome.org/show_bug.cgi?id=658721