Is it a bug - or is it a feature?

Hi all! This is a little bit offtopic here, I just want to know if someone else already had this effect... Yesterday I installed PHP-5beta3 on my server, wanted to try some things out. While testing with PEAR::Auth I noticed that login did not work. So I looked into it a little deeper, $_POST was empty after a submit - strange... I tested it with a little form on a otherwise blank page, and it worked. Huh? I played around with field-names and after I changed the names to "username" and "password", the names of the PEAR::Auth-loginfields, it didn't work anymore! Further tests showed that it's only the "username"-field. After changing it to "username2" everything worked fine again. So is this a known bug, that you can't use the name "username" for a form-element? Bye, Stephan