code: function getNaturalHeight(elementList, factor) {
      var q = {'$position': 'absolute', '$visibility': 'hidden', '$display': 'block', '$height': _null};
      var oldStyles = elementList['get'](q);
      var h = elementList['set'](q)['get']('clientHeight');
      elementList['set'](oldStyles);
      return h*factor + 'px';
    }
docs: finds out the 'natural' height of the first element, the one if $$slide=1