Why do some groups not have a margin option?

So I’ve got a “native” mobile app here. Everything’s on one page in different groups.

I’m trying to convert it from fixed width to responsive, so it can adapt to different phone widths.

Most of the groups are left justified. I want to change them to center justified, but most of them don’t have the option to change left/center/right margins. Any idea why not? As far as I can tell all the groups are setup the same way.

Group Home has the “fixed margin” option

Group Focus just doesn’t have that option

Along the same line, why is this group not getting wider? It should be expanding, right? No matter what I change it stays the same width even when the page gets wider.