I've given up on asking HOW, so now I'm just trying to understand WHY. Unless I'm mistaken, these are the only options, and their associated problems: 1. layout.css.devPixelsPerPx - changes UI along with web pages 2. Add-ons - don't work properly all the time - sometimes the fonts come out funny and the page layout changes (very different from using the native zoom if you compare side by side) Since there's already the ability to change the zoom level of a page, why can't a different default be set? There were only two things keeping me from switching from Chrome to Firefox - changing the default zoom, and enabling "highlight all" always for searching text (which is now available - yay). Come on, how hard can it be???