[Dovecot] LAYOUT=fs still uses 'dot' prefixes for folders

[PGNet Dev]

running latest dovecot HEAD, per,

	http://wiki.dovecot.org/MailLocation/Maildir

i've set LAYOUT=fs,

	dovecot -n| grep -i layout
		mail_location: maildir:/data/mail:LAYOUT=fs

and expect,

	maildirs to actually use physical directories, such as:
	    * Maildir/folder/
	    * Maildir/folder/subfolder/

but, autocreate at login creates folders using "dot" prefixes, e.g.,

	cd /data/mail/Domains/my.domain.com/Accounts/test_account
	ls -1d .*
		./
		../
		.Drafts/
		.Spam/
		.Templates/
		.Trash/

&, login via TBird, creating a folder "test", also creates

	.test/

a bug, or a misconfiguration?