code: static AjaxOperation registerContainer(final String triggerId, final String containerId,
  			final String containerContentId) {
  		AjaxOperation operation = new AjaxOperation(triggerId, containerContentId);
  		operation.setTargetContainerId(containerId);
  		operation.setAction(AjaxOperation.AjaxAction.REPLACE_CONTENT);
  		registerAjaxOperation(operation);
  		return operation;
  	}
docs: This internal method is used to register an arbitrary target container. It must only used by components which
  contain implicit AJAX capability.
  
  @param triggerId the id of the trigger that will cause the component to be painted.
  @param containerId the target container id. This is not necessarily a WComponent id.
  @param containerContentId the container content.
  @return the AjaxOperation control configuration object.