ZK UI plugin,the same as the ZKGrails plugin, seamlessly integrates ZK with Grails' infrastructures.
The difference is it uses the Grails' infrastructures more, such as gsp, controllers rather than zk's zul.
The html pages generated by gsp must generate the doc type as follows.
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
Add the tag <z:resources/> to the head of the layout/main.gsp or any page that you want to use ZK UI Grails plug-ins.
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<z:resources/>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Hello World Demo</title>
<z:resources/>
</head>
<body>
<z:window title="My First ZK UI Application" border="normal">
Hello World!
</z:window>
</body>
</html>
The official docs are here