docs: public void addNavButtons()
      {
          if ((m_iDisplayFieldDesc & ScreenConstants.SELECT_MODE) != ScreenConstants.SELECT_MODE)
              new SCannedBox(this.getNextLocation(ScreenConstants.FIRST_SCREEN_LOCATION, ScreenConstants.SET_ANCHOR), this, null, ScreenConstants.DEFAULT_DISPLAY, null, null, MenuConstants.DELETE, MenuConstants.DELETE, null);
          if (!(this.getParentScreen() instanceof Screen))
              super.addNavButtons();  // Only allow form screen if not sub-window
      }