Can't scroll registrant list

Hi,

When I click on registrant list to see all participant pop up window show only few last registrant and I cannot scroll down to see all of them although scroll button appear on the right side. This issue is on desktop view. On mobile the list do not appear at all.

Example of event: towarzysko.com/index.php/wydarzenia/wyda...cer-po-saskiej-kepie

Thanks,
Wirex