zkui support zk component, for use use z:ckeditor tag ,you must add ckez-3.6.0.1.jar(http://mavensync.zkoss.org/maven2/org/zkoss/zkforge/ckez/3.6.0.1/) to your project lib.
or you can use jar dependencies
mavenRepo "http://mavensync.zkoss.org/maven2/"
runtime "org.zkoss.zkforge:ckez:3.6.0.1"