After updating, the design, layout and text of firefox has 'blown up'; it's too large.
The only advice I consistently got after searching was to try View > Zoom etc.,
That only changed the screen I was in and reverted after changing to a new page, opening a new tab or restarting firefox.
I need a permanent solution where the firefox screen is where it was before.
Solved! Go to Solution.
Code changes regarding HiDPI support for high resolution displays have landed in Firefox 22 and later (bug #844604).
You can modify the layout.css.devPixelsPerPx and increase or decrease the value in 0.1 or 0.05 steps to adjust the size of fonts and other elements in Firefox.
Start with a value of 1 and adjust this value with 0.1 steps or 0.05 for finer adjustments.
EDIT by AliceWyman: To summarize:
Note that changes take effect immediately. To set it back to it's default value, right-click the preference and select Reset.
If web pages needs to be adjusted after changing this pref then you can look at the Default FullZoom Level or NoSquint extension.
Use this extension to adjust the font size for the user interface:
Firefox now tries to adjust the zoom level according to your Windows settings, as well as better supporting high DPI displays.
You can try adjusting the following setting:
(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.
(2) In the filter box, type or paste pix and pause while the list is filtered
(3) If layout.css.devPixelsPerPx has been customized from its default value of -1.0, right-click it and choose Reset to assess whether the default value works for you.
(4) Double-click layout.css.devPixelsPerPx and change its value to 1.0 for smaller fonts, or a larger ratio for larger fonts. For example, 1.25 corresponds to 125% font size in Windows display settings. You may need to switch back and forth to other windows/tabs to see how it's affecting them.
Can you find a good size?
More info in this thread: How do I set the default font size to a lower value?
If you cannot adjust both the "chrome" area and the "content" area to your liking simultaneously, you might need an extension to correct one or the other:
I can't return my old convinient scale with adjusting layout.css.devPixelsPerPx parameter.
Are there other ways to fix this annoying scale thing? Otherwise I'll have to downgrade to v.21