Inheritance and column references problem

The following SQL:

create table toinherit (
     id  integer primary key
);

create table leftside (
     leftname   varchar(64) not null unique
) inherits (toinherit);

create table rightside (
     rightname   varchar(64) not null unique
) inherits (toinherit);

create table linkthem (
     left_id     integer references toinherit (id),
     right_id    integer references toinherit (id)
);

insert into leftside (id, leftname) values (1, 'leftname1');
insert into rightside (id, rightname) values (2, 'rightname2');
insert into linkthem (left_id, right_id) values (1, 2);


...gives me this error:

CREATE TABLE
CREATE TABLE
INSERT 55919 1
INSERT 55920 1
psql:without_inherit.sql:24: ERROR:  insert or update on table
"linkthem" violates foreign key constraint "$1"
DETAIL:  Key (left_id)=(1) is not present in table "toinherit".


If I do the same thing but without using inheritance:

create table toinherit (
     id  integer primary key
);

create table leftside (
     id         integer references toinherit (id),
     leftname   varchar(64) not null unique
);

create table rightside (
     id         integer references toinherit (id),
     rightname   varchar(64) not null unique
);

create table linkthem (
     left_id     integer references toinherit (id),
     right_id    integer references toinherit (id)
);

insert into toinherit (id) values (1);
insert into toinherit (id) values (2);
insert into leftside (id, leftname) values (1, 'leftname1');
insert into rightside (id, rightname) values (2, 'rightname2');
insert into linkthem (left_id, right_id) values (1, 2);

...it works:

CREATE TABLE
CREATE TABLE
INSERT 55887 1
INSERT 55888 1
INSERT 55889 1
INSERT 55890 1
INSERT 55891 1


Is this a bug, or a feature? It seems I can't make a column reference
work directly with the table that gets inherited by the others. Neither
can I make a column reference work with a table that *inherits* the
toinherit table. If I can't get this to work, I'll have to revert back
to not using inheritance at all.

thanks,

/s.