plugins types FEATURE sort callback in string
diff --git a/src/plugins_types/string.c b/src/plugins_types/string.c
index b46e34a..5ae5204 100644
--- a/src/plugins_types/string.c
+++ b/src/plugins_types/string.c
@@ -129,7 +129,7 @@
         .plugin.store = lyplg_type_store_string,
         .plugin.validate = NULL,
         .plugin.compare = lyplg_type_compare_simple,
-        .plugin.sort = NULL,
+        .plugin.sort = lyplg_type_sort_simple,
         .plugin.print = lyplg_type_print_simple,
         .plugin.duplicate = lyplg_type_dup_simple,
         .plugin.free = lyplg_type_free_simple,