Forum OpenACS Q&A: Re: content_type__create_type for both item and revision table?

Bug tracker is an example of something that extends both cr_items and cr_revisions, although only having looked at the sql it looks like it does not in fact extend cr_items (even though th bt_bugs table pk references cr_items) since it does:
select acs_object_type__create_type (
    'bt_bug',
    'Bug',
    'Bugs',
    'acs_object',
    'bt_bugs',
    'bug_id',
    null,
    'f',
    null,
    'bt_bug__name'
);
I guess Lars could comment on whether that is simply a bug or is some sort of shortcoming with subclassing cr_item.