strange runtime message

[jsbien]

jsbien@VivoPC-D8:~$ LANG=pl_PL djview4poliqarp&
[1] 27896
jsbien@VivoPC-D8:~$ 
(process:27896): Gtk-WARNING **: Locale not supported by C library.
    Using the fallback 'C' locale.

Despite the message the sorting seems OK (without specyfying Polish locale the sorting is wrong as the default language of the system is English).

[Michał Rudolf]

This is Gtk/glibc error message, probably some problem with current Linux distribution/installation. I cannot do anything about it.