Effect.DropLeft = function(element) {
  element = $(element);
  var oldStyle = {
    top: element.getStyle('top'),
    left: element.getStyle('left'),
    opacity: element.getInlineOpacity() };
  return new Effect.Parallel(
    [ new Effect.Move(element, {x: 100, y: 0, sync: true }), 
      new Effect.Opacity(element, { sync: true, to: 0.0 }) ],
    Object.extend(
      { duration: 0.5,
        beforeSetup: function(effect) {
          effect.effects[0].element.makePositioned(); 
        },
        afterFinishInternal: function(effect) {
          effect.effects[0].element.hide().undoPositioned().setStyle(oldStyle);
        } 
      }, arguments[1] || {}));
}