case KeyCodes.KEY_UP:
nativeEvent.preventDefault();
scrollBy(diffScroll_, -getLineScroll(diffScroll_), 0);
break;
case KeyCodes.KEY_PAGEDOWN:
nativeEvent.preventDefault();
scrollBy(diffScroll_, getPageScroll(diffScroll_), 0);
break;
case KeyCodes.KEY_PAGEUP:
nativeEvent.preventDefault();
scrollBy(diffScroll_, -getPageScroll(diffScroll_), 0);