I've found a little bug about changing password through Control Panel.
If a user register his nickname with a special character (allowed in registation form), just like a dot, he is unable to change his password in Control Panel.
(Example of username: X.X.X.)
A error message like this appears:
Quote:Allowed characters for usernames are a-z, 0-9, -, _ and spaces.
This message appears everything the user try to change in his control panel.
Through ACP I manage to change everything about users with special character, with no warning and no errors.
I've phpBB XS 2 (build 058).