code: public void selectField(ScreenField sfCurrent, int iSelectField)
      {
          ScreenField sField = this.getComponentAfter(sfCurrent, iSelectField);
          if (sField != null)
              sField.requestFocus();
      }
docs: Move the focus to the next logical field.
  @param sfCurrent The currently selected screen field.
  @param iSelectField The screen field to select (next/prev/first/last).