PageBuilder: Row Spacing

I’ve read many, many posts by now on how to eliminate spaces between rows. I changed global page builder settings to 0 px between rows, edited bottom row margin to zero from the gear icon above the row, and even though the default row margins are zero, I put zeros anyway to be certain. Somehow there is still space between rows. Not that I want zero pixels of space between rows, but shouldn’t there be zero pixels between rows if that is the parameter I set ? I’m having issues because I’m playing with font sizing in different columns and rows and in certain cases I want the row below another to be IMMEDIATELY below the top row, but I cannot achieve this. Why ?