Drop table abort

It seem that a drop table while in a transaction keeps the table but not the
data. Bug? or undocumented feature?

testcase=> select * from t;
i
-
(0 rows)

testcase=> insert into t VALUES(1);
INSERT 551854 1
testcase=> insert into t VALUES(2);
INSERT 551855 1
testcase=> insert into t VALUES(3);
INSERT 551856 1
testcase=> select * from t;
i
-
1
2
3
(3 rows)

testcase=> begin;
BEGIN
testcase=> insert into t VALUES(4);
INSERT 551857 1
testcase=> drop table t;
DROP
testcase=> abort;
ABORT
testcase=> select * from t;
i
-
(0 rows)

testcase=> select version();
version
--------------------------------------------------------------
PostgreSQL 6.5.0 on i686-pc-linux-gnu, compiled by gcc 2.7.2.3