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Font Size of main content on all sites renders at 13px after waking from sleep

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All of a sudden, after waking my computer from sleep, I found that many websites in Firefox are displaying the main text content at 13px, ignoring font sizes specified in CSS etc. I first discovered this on my organization's website, I thought it was a browser cache issue, but it has persisted. The text content on our front page is all the correct size, but everything on the website that is "main content" text that is not in a heading tag, like blog post or regular page content, is rendered at 13px. Other sites like Wikipedia load this way as well. In private mode, the issue disappears. In Chrome, the issue does not occur.

I have cleared all cookies, browser cache, site data, history, and the problem persists. I have checked the default font settings in Firefox, the checkbox saying websites should override the font settings is already checked. Zoom is set to 100%. I updated to the latest version in the course of restarting, and it didn't fix the issue either.

In the attached screenshot, the examples on the left are in regular Firefox windows. On the top right, a page on our site is displayed correctly in Firefox private mode. In the bottom right, Wikipedia is displayed correctly in Google Chrome.

All of a sudden, after waking my computer from sleep, I found that many websites in Firefox are displaying the main text content at 13px, ignoring font sizes specified in CSS etc. I first discovered this on my organization's website, I thought it was a browser cache issue, but it has persisted. The text content on our front page is all the correct size, but everything on the website that is "main content" text that is not in a heading tag, like blog post or regular page content, is rendered at 13px. Other sites like Wikipedia load this way as well. In private mode, the issue disappears. In Chrome, the issue does not occur. I have cleared all cookies, browser cache, site data, history, and the problem persists. I have checked the default font settings in Firefox, the checkbox saying websites should override the font settings is already checked. Zoom is set to 100%. I updated to the latest version in the course of restarting, and it didn't fix the issue either. In the attached screenshot, the examples on the left are in regular Firefox windows. On the top right, a page on our site is displayed correctly in Firefox private mode. In the bottom right, Wikipedia is displayed correctly in Google Chrome.
Attached screenshots

Chosen solution

This came up in another thread, and I don't know whether it applies to you:

There is a bug in version 2.3.3 of the Facebook Container extension that causes font color problems. I have no idea whether it might also affect the font size.

Do you use this add-on? An update (version 2.3.4) was released a few hours ago which should fix it. Firefox should find it on a routine check at some point, but to speed that up:

Open the Add-ons page. Either:

  • Ctrl+Shift+a (Mac: Command+Shift+a)
  • "3-bar" menu button (or Tools menu) > Add-ons
  • type or paste about:addons in the address bar and press Enter/Return

In the right side, below the search box, there is a gear/wheel icon. Click that icon to drop the menu and then click "Check for Updates" to trigger an update.

Alternately, click Facebook Container to show its Details panel, scroll down below the description, and click "Check for Updates".

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All Replies (5)

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Hmm, what is going on there...

The base font size might be stored on a per-window basis, so to test whether a new regular window has the problem, click in the address bar of a page with the problem and press Shift+Enter to relaunch the URL in a new window. Does that one have the normal size or does it inherit the problem?

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Thanks for your reply! I just tried your suggestion and it inherits the problem when launched in a new window.

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Seçilmiş Həll

This came up in another thread, and I don't know whether it applies to you:

There is a bug in version 2.3.3 of the Facebook Container extension that causes font color problems. I have no idea whether it might also affect the font size.

Do you use this add-on? An update (version 2.3.4) was released a few hours ago which should fix it. Firefox should find it on a routine check at some point, but to speed that up:

Open the Add-ons page. Either:

  • Ctrl+Shift+a (Mac: Command+Shift+a)
  • "3-bar" menu button (or Tools menu) > Add-ons
  • type or paste about:addons in the address bar and press Enter/Return

In the right side, below the search box, there is a gear/wheel icon. Click that icon to drop the menu and then click "Check for Updates" to trigger an update.

Alternately, click Facebook Container to show its Details panel, scroll down below the description, and click "Check for Updates".

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This was the problem, thank you so much--it was driving me nuts!! After updating the extension everything loads correctly now.

I didn't see any color differences, just the font size issues.

This was a weird one... What threw me the most was that it persisted after deleting all data. Thanks again for your help—I think it would've driven me more crazy for the issue to suddenly disappear when the extension was auto-updated, leaving me wondering what happened. I'm glad I wrote in!

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Thank you for reporting back!