Hi Paul,
Yes, I am using SPPB v4 RC version and it's not a live website, I am working on it in my dev server. Unfortunately, it is not accessible yet, else I would let you see and try it yourself.
Here's the screencast capture:
https://take.ms/8ba3e
I am using JCE, I don't know if RC calls JCE when editing.
And here's what I am saying about the SPPB v4 RC version Module:
https://take.ms/NUAYSJ
In the screencast capture, you'll see that the module content occupies the entire width of the body but when editing it, the content is wrapped in a container with "<div class="sppb-row-container">" like I mentioned above. The edit layout is my desired layout. Also, you see it in the editor that since the content is in the middle, that means I did not enable the Fluid layout.
I don't think SPPB v4 is ready for Final Release unless your dev team has imported all the features from v3.x. I have been testing v4 it since Alpha and it has a lot of bugs. What bugs? Try to load your old layouts, pick a more complicated layouts like those with nested grids. Save and view it, you will get an error. Try to enable a SPPB Module, save it then try to edit it, you get an error.
Please let your dev know, don't remove the nested grid layout. Seems like as of RC they simplified the layout into a just 1 row > column + column. I cannot create a row > column > row > column + column.
Looking forward for v4 update, I'd rather see a more stable version than final release without fixing the issues I mentioned above.
Thanks,
Jackson