Fix bug ZK-1645: Incorrect display in IE 7 for tree component if user zoom to greater than 100%
http://tracker.zkoss.org/browse/ZK-1645
Fix bug ZK-1658: chosenbox disappears after user select a value
http://tracker.zkoss.org/browse/ZK-1658
Fix bug ZK-1660: Chosenbox with ListModel issue
http://tracker.zkoss.org/browse/ZK-1660