Side-by-side custom blocks v7.1

I want to create a custom, 2-3 column content block with custom spacing between the columns. 

Following the instructions on this layout help page., under the "Add new blocks" part

But my editor does not allow this. All I can do is add custom stacked elements. I can't move something and make it side-by-side.

Is this a limit in 7.1? 

Thanks

You know that thing where you ask a question and then immediately figure it out?

it worked fine all long. user error...