Setting Kopy blog into three columns

Hello there!

Wondering how to set the blog masonry into three columns.
In the actual theme demo, the three columns blog option is showing two columns only, but I’ve seen the theme offers the possibility to set it to three (in the “Home Theme Overview”, under Customized Pages slider (slider nº4).

Now in Appearance > Theme Options > Blog Options, I’ve set the “Blog Overview Style” to Masonry and the “Masonry Options” to: grid boxes – same widths, auto heights and three columns. Unfortunately only two columns are displayed.

Hope you can help!
Many thanks :)

Best,