protected function _countActivatedExtensions($aModuleExtensions, $aInstalledExtensions)
    {
        $iActive = 0;
        foreach ($aModuleExtensions as $sClass => $mExtension) {
            if (is_array($mExtension)) {
                foreach ($mExtension as $sExtension) {
                    if ((isset($aInstalledExtensions[$sClass]) && in_array($sExtension, $aInstalledExtensions[$sClass]))) {
                        $iActive++;
                    }
                }
            } elseif ((isset($aInstalledExtensions[$sClass]) && in_array($mExtension, $aInstalledExtensions[$sClass]))) {
                $iActive++;
            }
        }

        return $iActive;
    }