Bug fixed ZK-2028: When deleted one selected item in chosenbox with
ListSubModel, it would remove all the selection
http://tracker.zkoss.org/browse/ZK-2028
Bug fixed B65-ZK-2019: Chosenbox work incorrectly when using
ListSubModel and Comparator
http://tracker.zkoss.org/browse/ZK-2019
Bug fixed ZK-2047: IE Datebox calendar overlapping pdf problem
http://tracker.zkoss.org/browse/ZK-2047

Bug refixed ZK-1904: Datebox doesn't sync dropdown stackup well (IE only)
Merge remote-tracking branch 'Raymond/B65-ZK-2019' into 6.5