Automatically tick container box when subpage

<?php
/* SetContainerStatus Plugin */

/* Connect to OnDocFormSave, OnResourceDelete, onResourceDuplicate, and OnResourceUndelete */
/* @var $modx modX */
/* @var $parent modResource */
/* @var $newParent modResource */
/* @var $doc modResource */

switch ($modx->event->name) {
    case 'OnDocFormSave':

        $children = $resource->getMany('Children');
        if (!empty($children)) {
            $resource->set('isfolder', true);
            $resource->save();
        }
        $parent = $resource->getOne('parent');

        if ($parent) {
            $parent->set('isfolder', true);
            $parent->save();
        }
        break;

    case 'OnResourceDelete':
        /* get parent object (if any) */
        $parent = $resource->getOne('Parent');
        if ($parent) {
            /* check for siblings */
            $children = $parent->getMany('Children');
            if (empty($children)) {
                $parent->set('isfolder', false);
                $parent->save();
            }
        }
        break;

    case 'OnResourceUnDelete':
        $parent = $resource->getOne('Parent');

        if ($parent) {
            if (! $parent->get('isfolder')) {
                $parent->set('isfolder', true);
                $parent->save();
            }
        }
        break;
    case 'OnResourceDuplicate':
        $newChildren = $newResource->getMany('Children');
        if (!empty($newChildren)) {
            $newResource->set('isfolder', true);
            $newResource->save();
        }
        $newParent = $newResource->getOne('Parent');
        if ($newParent) {
            if (! $newParent->get('isfolder')) {
                $newParent->set('isfolder', true);
                $newParent->save();
            }
        }

        break;
}

<?php
/* Utility snippet to set container status for all existing resources */

$docs = $modx->getIterator('modResource');

foreach ($docs as $doc) {
    $children = $doc->getMany('Children');

    if ($children) {
        if (! $doc->get('isfolder')) {
            $doc->set('isfolder', true);
            $doc->save();
        }
    }
}

<?php
/* Utility snippet to set container status for all existing resources */
 
$docs = $modx->getIterator('modResource');
 
foreach ($docs as $doc) {
    $children = $doc->getMany('Children', array('deleted' => 0));
    $setting = ! empty($children)? true : false;
    if ($setting != $doc->get('isFolder')) {
        $doc->set('isFolder', $setting);
        $doc->save(); 
    }
    unset($children);
}