gtk_object_add_arg_type ("GtkCList::row_height", GTK_TYPE_UINT, GTK_ARG_READWRITE, ARG_ROW_HEIGHT); my guess is that you just need to use "row_height" rather than "row-height". I haven't tried it 'cause I don't have any clist code lying around, but it should be easy for you to test. /mailund -- Atheists are people who have no invisible means of support