if (this.baseItemLabelGenerator != null) {
            if (this.baseItemLabelGenerator instanceof PublicCloneable) {
                PublicCloneable pc
                        = (PublicCloneable) this.baseItemLabelGenerator;
                clone.baseItemLabelGenerator
                        = (CategoryItemLabelGenerator) pc.clone();
            }
            else {
                throw new CloneNotSupportedException(
                        "ItemLabelGenerator not cloneable.");