No - it isn’t at all. Box Model was the “semantical wrong syntax” for a pretty easy thing:
or inflow-construction in FreewayPro. We simply haven’t had a better name for it. I later called it GridMeister - too late to be honest.
But FreewayPro is the mentioned app that had a lot of cool things in it. The concept is totally different though - because FreewayPro as an app with a native file had (has) kind of a processing (pre/post).
Allow me an example:
You applied the action to a div of your liking. A context window appeared where in you added the required stuff - hit CMD-P, and all of a sudden, Freeway put the required code stuff to the dedicated place(s). This was convenient - easy - simple.
Unfortunately, I’m not aware on how to get something like this into Pinegrow - or if it is even possible. But if so, I could see an endless number of unobtrusive lil helpers for the basic PG-core.