Blank part on portfolio sortable page

Hi Guys,

Good morning.

I am using the portfolio sortable layout, I have a problem now.

For example, there are 100 portfolio items on the page, 5 portfolio categories. When the 100 items displayed on page, the bottom of page is the footer, this is OK, but when I click a specific category with 15 items under it, there will be a blank part under footer, it looks not good.

I am using the theme locally, not on line yet, so I can only show you a picture on dropbox.

Here is the link: https://www.dropbox.com/s/clnchdx4h8gicq7/Blank%20Part.jpg?dl=0

Do you know how to solve this?