I tried a dirty hack: adding gtk-icon-sizes = "panel-menu=24,24" to /usr/share/themes/Clearlooks/gtk-2.0/gtkrc. And now all my Clearlooks icons are perfect in the menus. Should we only fix the erroneous themes (they are in gnome-themes)? Would you set the importance of this bug and confirm it? I can easily imagine you don't have time to waste, but for sure there's somebody that has and cares about it. You can't simply assume that all users stay with Human.