zk.xml Editor
From Documentation
The zk.xml Editor helps you edit ZK configuration file (the file under your project's WEB-INF/zk.xml). The editor can be opened by right clicking the zk.xml file and selecting [Open With]/[XML Editor for zk.xml] from the context menu.
The zk.xml editor provides content assist when editing the ZK configuration file. For detailed descriptions of every element in zk.xml, please refer to ZK Configuration Reference : zk.xml