i'm really ashamed of this.
dataobjectmanager has become a significant part of silverstripe for me, so i completely missed the fact it doesn't come with svn updates of the core. it definitely should, but that's no excuse, i know.
just updated and everything's fine as usual.
unclecheese, so sorry for wasting your time.
at least, maybe this thread reminds others being more clever than i've been and running updateds before asking.
[edit:] a last, hopefully helpful comment for others concerning the bugfix to replace a 'Title' by a custom 'Name' field: in case you still rely on the 'Title' field in some other context, you may have the following in you page class:
function onBeforeWrite() {
$this->Title = $this->Name;
$this->MenuTitle = $this->Name;
parent::onBeforeWrite();
}
