Formhelp doesn't work

The Sitellite API states:

"New in 4.0: - FormHelp ins now integrated into MailForm. In settings.php, you can specify 'formhelp = yes' under [Form] and 'formhelp = Message' under any widget and the display of it is automatic."

I tried this, but it doensn't work. The "old way":

extra = "id=changelog onfocus=formhelp_show (this, 'The change summary helps give other site editors, including yourself, a more complete history of the changes that have been made to this document.') onblur=formhelp_hide ()"

Does work.