- when building your app, you need both metawidget.jar and metawidget-gwt-client.jar in your compiler CLASSPATH
- when deploying your app, you need metawidget.jar in your WEB-INF/lib and a reference to GwtRemoteInspectorImpl in your web.xml
- you can see this in action in addressbook-gwt.war in the binary distribution
- you may also find the example-gwt-addressbook Ant task in the source distribution's build.xml useful
Thanks to the anonymous bug reporter for highlighting this lack of documentation!