code: protected void addDefaultOnChangeProcessors() {
          onChangeProcessors.add(new ButtonOnChangeProcessor());
          onChangeProcessors.add(new ListOnChangeProcessor());
          onChangeProcessors.add(new ListSingleItemOnChangeProcessor());
          onChangeProcessors.add(new ProgressBarOnChangeProcessor());
          onChangeProcessors.add(new SelectBoxOnChangeProcessor());
          onChangeProcessors.add(new SelectBoxSingleItemOnChangeProcessor());
          onChangeProcessors.add(new TextFieldOnChangeProcessor());
      }
docs: Adds default on change processors. Warning: used by the constructor.