Page Limit

I'm currently using GrapesJS as a Letter/Form Composer, and it's been working wonderfully so far. However I'm just finishing up the last few requirementsI'm scaling the canvas to the size of an A4 piece of paper so that when it prints, everything is consistent with the form they've built. However, I'm unsure whether or not there's a way of limiting my user from creating new lines once they've reached the "end" of the page. I have a height on both my editor, and my canvas. Yet this still does not prevent the user from hitting "enter" repeatedly to make the paper grow. ^ If there is no way to l...