org.zkoss.zk.ui.EmulateIE7
From Documentation
Property:
org.zkoss.zk.ui.EmulateIE7
Default: false [since 5.0.2]
It specifies whether to make Internet Explorer 8 running in IE7 compatible mode. It is used if some of your JavaScript code doesn't work well in IE8.
Refer to Introducing IE=EmulateIE7