> but I wanted to work out calculations on a single screen without the code/renderer split screen setup (having the math directly visible is a game-changer for doing long calculations, by the way).

If anyone wants to play with this there are 'online editors' so you don't even have to download/install software nowadays:

* https://latex.codecogs.com/eqneditor/editor.php

This one renders on-screen, as well as allowing downloads as GIF/PNG/PDF/SVG to perhaps embed in other document systems. (Plenty of others as well.)