steps to reproduce

http://zkfiddle.org/sample/3rnm1e1/1-Grid-ROD-Autosort-LiveGridDataLoader-Exception
-run fiddle
-press the button

actual result

A UIException is thrown :
org.zkoss.zk.ui.UiException: Removal causes a larger list?
at org.zkoss.zkmax.zul.impl.LiveGridDataLoader.doLiveListDataChange(LiveGridDataLoader.java:119)

expected result

The listmodel is cleared, then 2 items are added, then the first item is removed.
This happen if deactivating one of the ROD or AutoSort attribute.

root cause

It seem that with ROD and AutoSort, the _oldTotalSize field of LiveGridDataLoader is not updated when adding items throught ListModelList.add, addAll, etc