Top margin in generateblocks container

I have the generateblocks installed and I must say that an excellent block editor. I post this here since I don't see support forum on the respective page. If it is the wrong place, you can simply delete it.

My problems is that when I add top margin to a container, at the same time a lower margin (or space) is added in the container which lengthens it down. I set the margin below 0, but it still appears.

Is this normal? Or is there something I'm doing wrong?

If I don't add the top margin this space is not created.

http://imgfz.com/i/8aQk0fT.png

I use the latest version of generateblocks: RC 2.

I'd appreciate your help.