filter.php

<?php
 
namespace Bitrix\Calendar\Integration\UI\EntitySelector\JointSharing;
 
use Bitrix\UI\EntitySelector\BaseFilter;
use Bitrix\UI\EntitySelector\Dialog;
use Bitrix\UI\EntitySelector\Item;
 
 
class Filter extends BaseFilter
{
    public function __construct()
    {
        parent::__construct();
    }
 
    public function isAvailable(): bool
    {
        return $GLOBALS['USER']->isAuthorized();
    }
 
    public function apply(array $items, Dialog $dialog): void
    {
        $currentUserId = \CCalendar::GetCurUserId();
 
        foreach ($items as $item)
        {
            if (!($item instanceof Item))
            {
                continue;
            }
 
            if ($item->getId() === $currentUserId)
            {
                $item->setDeselectable(false);
            }
        }
    }
}