Appending to a new container doesn't fully remove from former parent container

[codeinabox]

I am not sure this is a bug but when appending an Agility object to a new container it doesn't fully remove it from former parent container. At the moment I have to manually remove it from its former parent eg

        moveToContainer = function(entity, oldContainer, newContainer) {
            oldContainer.remove(entity._id);
            newContainer.append(entity);
        };