2 coloms instead 3

Goodday,

Downloaded your great plugin this weekend. Started to make a grid with 3 columns.
After finishing the grid and putting it into a page it only shows 2 columns.
I tested every other option, but still only 2 columns.

Lay-out settings:
Lay-out 1
Column 3
Display per page 6

If i change the settings to 4 columns, it also leaves a big gap of white on the left side of the page.

Any tips/advise/solutions to this problem? I really hope you can help me bringing things back to a 3 column grid!

Thx