We can't bind/unbind the entire keydown event here - this will remove handlers that the user has entered as well.  Ideally we could just bind the keydown event to the `container` object instead of the document, but if that doesn't give the desired behavior, we should have a named function that gets bound and unbound directly.

    $(doc).bind("keydown", closeOnEnter);
    ...
    $(doc).unbind("keydown", closeOnEnter);