I'm using Ubuntu 16.04 and Firefox 50.1 with an external monitor attached to my laptop. My laptop screen is 14-inch 1080p which has a scale factor of 1.25 in System Settings. My external monitor is 22-inch 1080p which has a scale factor of 1. And in my about:config, I set the layout.css.devPixelsPerPx to -1.0.

When I set the scale factor to match the smallest controls in System Settings, Firefox becomes tiny on my laptop screen. Not completely unusable, but annoying.

Is there anyway to get per-monitor DPI scaling on Firefox? Especially natively without installing new extensions? Firefox can already handle this on Windows 10.


I'm using the following AutoHiDPI extension for Firefox and it scales pretty well in Ubuntu 17.04:


  • @Zanna: You're right, whoops! – user364819 May 26 '17 at 21:44

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