function populateActivities($projectId, $row, $activityId = null, $activityName = null)
{
    ob_clean();
    require ROOT_PATH . '/language/default/lang_default_full.php';
    $timeController = new TimeController();
    $projectActivities = $timeController->fetchProjectActivities($projectId);
    $objResponse = new xajaxResponse();
    $xajaxFiller = new xajaxElementFiller();
    $xajaxFiller->setDefaultOptionName($GLOBALS['lang_Common_Select']);
    $element = "cmbActivity[{$row}]";
    if (count($projectActivities) == 0) {
        $projectActivities[0][0] = -1;
        $projectActivities[0][1] = "- {$lang_Time_Timesheet_SelectProject} -";
        $objResponse = $xajaxFiller->cmbFillerById($objResponse, $projectActivities, 0, 'frmTimesheet', $element, 0);
    } else {
        if ($activityId != null) {
            $projectActivityObject = new ProjectActivity();
            if ($projectId == $projectActivityObject->retrieveActivityProjectId($activityId)) {
                $activityExists = false;
                $i = 0;
                foreach ($projectActivities as $activity) {
                    if ($activity[$i][0] == $activityId) {
                        $activityExists = true;
                    }
                    $i++;
                }
                if (!$activityExists) {
                    $count = count($projectActivities);
                    $projectActivities[$count][0] = $activityId;
                    $projectActivities[$count][1] = $activityName;
                }
            }
        }
        $objResponse->addScript("document.getElementById('" . $element . "').options.length = 0;");
        $objResponse->addScript("document.getElementById('" . $element . "').options[0] = new Option('- {$lang_Common_Select} -','-1');");
        $objResponse = $xajaxFiller->cmbFillerById($objResponse, $projectActivities, 0, 'frmTimesheet', $element, 1);
    }
    $objResponse->addScript('document.getElementById("' . $element . '").focus();');
    $objResponse->addAssign('status', 'innerHTML', '');
    return $objResponse->getXML();
}