@Override
  public String get_ValueAsString(String variableName) {
    ADWindow adwindow = ADWindow.get(windowNo);
    if (adwindow == null) return "";

    IADTabpanel adTabpanel = adwindow.getADWindowContent().getADTab().getSelectedTabpanel();
    if (adTabpanel == null) return "";

    int tabNo = adTabpanel.getTabNo();
    if (tabNo == 0) return adTabpanel.get_ValueAsString(variableName);
    else return Env.getContext(Env.getCtx(), windowNo, tabNo, variableName, false, true);
  }