BUG #2758: missing quotes in SQL sentence

The following bug has been logged online:

Bug reference:      2758
Logged by:          scoanda
Email address:      sabin.coanda@deuromedia.ro
PostgreSQL version: 8.1.4
Operating system:   Windows XP sp2
Description:        missing quotes in SQL sentence
Details:

I set the transaction isolation level for an user with
ALTER ROLE <user> SET default_transaction_isolation='read committed';

In pgAdmin I get the sentence without quotes:
ALTER ROLE <user> SET default_transaction_isolation=read committed;

This doesn't work if I copy/paste to SQL Query window.