White space appears under gallery when resizing the browser

There an issue with the gallery that I can’t seem to resolve. When resize my browser window, I get this white space underneath the gallery.

This resize issue appears only when you reduce the browser size. When you increase the browser size, everything works good.

Here is a short video where I show this problem in greater details.

I am using the latest version of the gallery. I upgraded it specifically to solve this problem, but the problem persists.

The page I need help with: [log in to see the link]