BUG #1335: Wrong sort result in union queries

The following bug has been logged online:

Bug reference:      1335
Logged by:          snaky

Email address:      snaky@ulstu.ru

PostgreSQL version: 8.0 Beta

Operating system:   Windows 2003/XP

Description:        Wrong sort result in union queries

Details:

sorry for my english.

Query:
select 2 union select 1

Result:
1
2

Why? I think the result must be like this:
2
1

Why PostgreSQL sort union queries by first column by default?
Certainly, I understand that I can write general "order by" in the end of
query. However, in this case, I can't make queries with "manual" row ording.
And what is more, this query does not work properly:

(select * from (select 1, 2 union select 4, 3) as a
order by 2 desc)
union
select 1, 1

Result must be like this:
4, 3
1, 2
1, 1

but real result is:
1, 1
1, 2
4, 3


Full version info:
PostgreSQL 8.0.0beta1 on i686-pc-mingw32, compiled by GCC gcc.exe (GCC)
3.2.3 (mingw special 20030504-1)