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Windows Update caused browser resizing

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It seems a Windows 8.1 update Aug 10, 2022 made my FF browser enlarge on my second screen from my laptop. Moving it back to the laptop makes it return to the correct size. I've tried the resolution, zoom, etc. Not sure what's happened to it to cause the enlargement. Zoom only works on the pages, not the tabs. It's the whole browser that is bigger, including the tabs. Open to suggestions.

It seems a Windows 8.1 update Aug 10, 2022 made my FF browser enlarge on my second screen from my laptop. Moving it back to the laptop makes it return to the correct size. I've tried the resolution, zoom, etc. Not sure what's happened to it to cause the enlargement. Zoom only works on the pages, not the tabs. It's the whole browser that is bigger, including the tabs. Open to suggestions.

All Replies (2)

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It's not you, it's Firefox.

Firefox 103 now applies the Windows "Make text bigger" setting as a zoom multiplier (Release Notes).

Your options:

(A) If you do not need "Make text bigger" for other applications, the simplest thing you can do is reset that to 100% to resolve the issue. This screenshot is from Windows 10 so I'm not sure how well it matches what you see on Windows 8.1:



(B) Firefox 103 has 3 interrelated hidden settings that control the overall zoom level and whether it considers information from the system.

First-Level Tweak

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste os-zoom and pause while the list is filtered

(3) Double-click the browser.display.os-zoom-behavior preference to display an editing field, and change the value to 0 then press Enter or click the blue check mark button to save the change.

For reference, these are the accepted values:

  • 0 => Ignore the OS-level scaling
  • 1 => Apply OS-level scaling as proportional zoom [default in Firefox 103]
  • 2 => Apply OS-level scaling as text-only zoom

Second-Level Tweak

If the above doesn't resolve the issue, this is the one to try next:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste ui.textScaleFactor and pause while the list is filtered.

Normally, Firefox will display a bar with Boolean Number String and a plus button. If Firefox displays a row that already has a number value, skip to step 5.

(3) Click the circular button in front of Number and then click the + button to create a new preference. (See composite screenshot below.)

(4) Firefox should display an editing field, and show a value of 0 -- edit the value to 100 then press Enter or click the blue check mark button to save the change.

(5) If the current value of ui.textScaleFactor is NOT 100, then double-click the preference to display an editing field, and change the value to 100 then press Enter or click the blue check mark button to save the change.

If 100 doesn't work well, try adjusting in small increments (like 110 or 90) to see what value works well for you.

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I just realized that I don't know how to make these adjustments on only one of your displays, so if these changes mess up your main display, change those back and I guess we'll have to wait for additional suggestions.