code: public String getDefaultFormsParam()
      {
          if (this.getScreenField().getParentScreen() != null)
              return ((ZScreenField)this.getScreenField().getParentScreen().getScreenFieldView()).getDefaultFormsParam();
          else
              return null;
      }
docs: Get the Forms param to be passed on submit.
  @return  The hidden "forms" param to be passed on submit (input/diplay/both/bothifdata).