Sun Microsystems recommends that you use the UTF-8 and the zh_CN.GB18030 locales even though other legacy locales are listed in the login screen. When you manually switch from the default login screen to the GNOME 2.x Display Manager, only the UTF-8 and zh_CN.GB18030 locales are available. If you want to add the legacy locales on your GNOME 2.x Display Manager login screen, remove the comment tags surrounding the entries for the locales in /etc/X11/gdm/locale.alias file and then reboot your system.