Hi Ofi,
Thanks for the pointing out that settings.
By the way, why is the SPPB module behave like this by default? Like I said, if you look at the html structure when editing, there is a div with a class where the width of the section row is set just like bootstrap "container" class is. But when you go out of the editor, that container disappear.
Anyhow, I added a class "container" in the Row Section Settings and that fixed my issue. But still my question above, when someone use the pre-made layouts, it is kind of confusing. I think this is happening to some pre-made layouts only.
Anyhow, thanks again!
Jackson