Bug: table inheritance. Trigger before DELETE for each statement is ignored

Version: postgresql 9.0.1
Step to reproduce: use following code. It creates two tables (parent
"xtest" and inherited "xtest_inh"), creates trigger function, creates
BEFORE INSERT/UPDATE/DELETE trigger.

*************************************
CREATE TABLE xtest (id serial, data varchar, primary key(id));
CREATE TABLE xtest_inh (check (id > 0), primary key(id))
INHERITS (xtest);

-- insert some data to inherited table "xtest_inh"
INSERT INTO xtest_inh(data) values ('ddd'), ('lol'), ('olo');

-- this function just raises an exception every time
CREATE FUNCTION just_raise_exception_tg() returns trigger as $$
BEGIN
raise exception 'aaaaaaaaaaaaaaaaaaaaa!';
END; $$ language plpgsql;

-- adding STATEMENT-level trigger to inherited table "xtest_inh"
CREATE TRIGGER just_raise_exception_tg
BEFORE INSERT OR UPDATE OF data OR DELETE ON xtest_inh
FOR EACH STATEMENT execute procedure just_raise_exception_tg(2);

-- do some operations, that should cause to trigger the table
-- INSERT into xtest_inh(data) values ('omg');
DELETE from xtest where id = 2;

drop table xtest cascade;
drop function just_raise_exception_tg() cascade;

**********************************

Expected result: exception will be raised before deletion of rows is
done.

Real result: no exception occurs. One of rows is really deleted.
The trigger is ignored.

Comments:
1. You can uncomment INSERT statement, and try again: exception
will be thrown. BEFORE INSERT works, BEFORE delete - no.
2. If i create trigger FOR EACH STATEMENT, it will work ok for insert,
update and delete.
3. AFTER DELETE statement-level trigger also does not work at all.

bug?