Need Wappler Expert Help

Hi,
I redesigned a client web site with Wappler where there’s a script (from phpjabbars) I am using as a catalog (My next step is to rebuild this catalog with Wappler).
But till then, there is a strange issue that, according to phpjabbers is most likely caused by something in the page code
.
The problem: After clicking a image in the catalog this open a Lightbox that show on top of the page but scrolling the images is causing the Lightbox to move down the page and visitors have to scroll down to get back to images again and this is annoying particularly on cellphones. There was no such issue before rebuilding the site design with Wappler.
See here: https://vr-surlepouceinc.com/location.php?controller=pjListings&action=pjActionView&id=10

So I am asking for some help from the experts here, if someone would be kind enough to take a look at it and at least give me a hint about what is causing this.

Any help will be much appreciated.

Thank you very much