Steps to Reproduce

1. Enable Embedded ZK
(in zk.xml)

<library-property>
	<name>org.zkoss.web.servlet.http.embedded.enabled</name>
	<value>true</value>
</library-property>

2. run attached html (with zul)

3. click buttons

Current Result

unexpected exception

Expected Result

no exception

Debug Information

Workaround