To give further clarification this bug most probably will be of concern to those who use Xfce or LXDE, or other lightweight DE/WM. GNOME uses gksu while KDE uses kdesu. Gksu on the otherhand may be used by Gtk-based environments. Sux is for the minimalistic and terminal-inclined
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By having _only_ sux installed, without the presence of its alternatives like gksu, kdesu, ktsuss, etc., 'su-to-root -X' will use sux, and you will know this when you're presented with a terminal asking for root password before running an app from the menu that requires root privilege.
Moreover, the bug seems to only manifest to applications that are run from /usr/bin, such as GSmartControl (/usr/bin/gsmartcontrol). Applications that run from /usr/sbin, such as Synaptic (/usr/sbin/synaptic) are not affected.