Additional Interfaces that might be implemented by the returned object of getExtraCtrl(). ZK uses them to decide how to render a component specially.
See also getExtraCtrl
Application developers need NOT to access any of them.
z.chchg
Once a component implements this interface and ChildChangedAware.isChildChangedAware returns true, the z.chchg command is sent to the client to update the visual representation.