hello, firefox 22 is now respecting the pixel density you've set on a system level in the windows control panel > appearance > display. more information about that is available at http://windows.microsoft.com/en-us/windows7/make-the-text-on-your-screen-larger-or-smaller

if you want to set the text size/pixel density in firefox different from that of your system's settings like it was handled in prior versions, enter about:config into the firefox address bar (confirm the info message in case it shows up) & search for the preference named layout.css.devPixelsPerPx. double-click it and change its value to 1.0 (or any other zoom factor that fits your purpose; -1.0 is the default value and will adhere to the system settings).

Thank you very much :D But i cant quite find a value that fits with the old ratio. And if i turn down the ratio in Windows from 125% to 100 everything looks a bit weird.. P.S. I am using a 17.3 Inch screen.

You can modify the layout.css.devPixelsPerPx pref to adjust the size of all elements including the fonts in Firefox.

If you need to make further adjustments then start with a value of 1.0 and adjust this value with 0.1 steps or 0.05 for finer adjustments.

• Use values between 1.0 and about 0.5 to reduce elements in size (do NOT go all the way to 0.05!)
• Use values greater than 1.0 to magnify and make elements larger (percentage divided by DPI, % / DPI).

• https://support.mozilla.org/kb/forum-response-Zoom-feature-on-Firefox-22
• http://kb.mozillazine.org/about:config

If web pages needs to be adjusted after changing this pref then you can look at the Default FullZoom Level or NoSquint extension.

• Default FullZoom Level: https://addons.mozilla.org/firefox/addon/default-fullzoom-level/
• NoSquint: https://addons.mozilla.org/firefox/addon/nosquint/

Use this extension to adjust the font size for the user interface:

• Theme Font & Size Changer: https://addons.mozilla.org/firefox/addon/theme-font-size-changer/