code: public int getActiveTab() {
  
          if (m_activeTab < 0) {
              String paramTab = getParamTab();
              int tab = 1;
              if (CmsStringUtil.isNotEmpty(paramTab)) {
                  try {
                      tab = Integer.parseInt(paramTab);
                  } catch (NumberFormatException e) {
                      // do nothing, the first tab is returned
                      if (LOG.isInfoEnabled()) {
                          LOG.info(e.getLocalizedMessage());
                      }
                  }
              }
              setParamTab("" + tab);
              m_activeTab = tab;
              return tab;
          } else {
              return m_activeTab;
          }
      }
docs: Returns the number of the currently active tab depending on the request parameter.<p>
  
  This method has to be called once in initWorkplaceRequestValues after filling the request parameters.<p>
  
  @return the number of the currently active tab