I wouldn’t like to spam here so if there’s a need to transfer my posts to some new topic, let me know.
I did some trial and error operations (deleting the floor, resetting tags, purging, cutting and pasting to another file then back to project file etc.)
At some point I noticed that the grid I get in Layout looks very much like the grid I see when I assign ConDoc Tags. See pictures below. It looks even more similar when you change the Viewport Resolution in Layout to High.
