code: @Override
      public String paramsAsHidden() {
  
          StringBuffer result = new StringBuffer(512);
          String activeTab = getTabParameterOrder().get(getActiveTab() - 1);
          Map<String, Object> params = paramValues();
          Iterator<Entry<String, Object>> i = params.entrySet().iterator();
          while (i.hasNext()) {
              Entry<String, Object> entry = i.next();
              String param = entry.getKey();
              if (!param.startsWith(activeTab)) {
                  // add only parameters which are not displayed in currently active tab
                  result.append("<input type=\"hidden\" name=\"");
                  result.append(param);
                  result.append("\" value=\"");
                  result.append(
                      CmsEncoder.encode(entry.getValue().toString(), getCms().getRequestContext().getEncoding()));
                  result.append("\">\n");
              }
          }
          return result.toString();
      }
docs: Returns all initialized parameters of the current workplace class
  as hidden field tags that can be inserted in a form.<p>
  
  This overwrites the method in CmsWorkplace because for each tab,
  only the hidden parameters of the non displayed tabs are added.<p>
  
  @return all initialized parameters of the current workplace class
  as hidden field tags that can be inserted in a html form