fixed crash when editing user with 'user login' check box

source/ubl-settings-usergroups.c

@@ -1986,7 +1986,7 @@ void on_user_save(GtkWidget *self, dictionary *dict){
 			for (int i=0;i<final_size;i++){
 				int parsed_size;
 				config_str parsed = yon_char_parse(final[i],&parsed_size,":");
-				if (parsed_size>1&&!strcmp(parsed[2],uid_string)&&strcmp(parsed[2],window->last_uid)) found = 1;
+				if (parsed_size>1&&!strcmp(parsed[2],uid_string)&&(yon_char_is_empty(window->last_uid)&&strcmp(parsed[2],window->last_uid))) found = 1;
 				if (parsed_size) yon_char_parsed_free(parsed,parsed_size);
 			}
 			if (found){