_film_changed_connection = film->Change.connect (bind (&Timeline::film_change, this, _1, _2));
_film_content_change_connection = film->ContentChange.connect (bind (&Timeline::film_content_change, this, _1, _3, _4));
_film_changed_connection = film->Change.connect (bind (&Timeline::film_change, this, _1, _2));
_film_content_change_connection = film->ContentChange.connect (bind (&Timeline::film_content_change, this, _1, _3, _4));