public class DesktopForm extends AbstractForm {

  @Order(10.0)
  public class MainBox extends AbstractGroupBox {

    @Order(10.0)
    public class TextField extends AbstractTextField {

      @Override
      protected String getConfiguredLabel() {
        return TEXTS.get("Text");
      }
    }

    @Order(20.0)
    public class TabBox extends AbstractTabBox {

      @Override
      protected String getConfiguredLabel() {
        return TEXTS.get("TabBox");
      }

      @Order(10.0)
      public class Tab1Box extends AbstractGroupBox {

        @Override
        protected String getConfiguredLabel() {
          return TEXTS.get("Tab1");
        }

        @Order(10.0)
        public class Label1Field extends AbstractLabelField {

          @Override
          protected String getConfiguredLabel() {
            return TEXTS.get("Label1");
          }

          @Override
          protected Class<? extends IValueField> getConfiguredMasterField() {
            return DesktopForm.MainBox.TextField.class;
          }

          @Override
          protected boolean getConfiguredMasterRequired() {
            return true;
          }

          @Override
          protected void execChangedMasterValue(Object newMasterValue) throws ProcessingException {
            super.execChangedMasterValue(newMasterValue);
            setDisplayText((String) newMasterValue);
          }
        }
      }
    }
}

DesktopForm
|-MainBox
    |-Group1
        |-TextField
    |-Group2
        |-TabBox
            |-Tab1
                |-Label