When I remove elements from a t4 page builder site using the Drone page. I get a white bar on the page and I'm not sure what could be causing it. Certain elements added or taken out change the size or shape of it 
Issue with t4 page builder.
Hi
It's padding value set for the mainbody section of template:
If you want to override this style, you can use this custom css:
.item-101 .t4-main-body {
padding-bottom: 0 !important;
}