combo slow with 800 items

i have a combo preloaded with data, however, when clicking on it - the combo takes too long (5 seconds) to pop the data. any help ???

great. it fixed one problem and causes another problem. when that line is inserted (list.setItemTemplate(new AW.Templates.Cell)), the following line within obj.showPopup = function(). does not work (this.getPopupTemplate().getScrollTemplate().element().parentNode.scrollTop = this.getCurrentItem() * 16.0;)

i.e. aligning the selector with the scroll