Mantis 1.2.3 new user sign up

[epubsinc]

Just getting this installed and configured and I'm running into something weird.

When my config file has the lines

$g_allow_signup = ON;
$g_enable_email_notification = OFF;

new users aren't allowed to sign up. However,

$g_allow_signup = ON;
$g_enable_email_notification = ON;

allows new users to sign up. Is this a bug? The way I read the config you can have it both ways. If email notification is off, new users can sign up, their password will be blank and they won't get an email notification,

Jim