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Update ruined pdfviewer design

  • 4 replies
  • 1 has this problem
  • Last reply by jscher2000

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Update came and I became furious that the pdfviewer is changed (I could write you a 300 page book why the forced UI and changes to user settings are terrible and hated everywhere). I would like to use the previous version (with the dark background), not this white version which burns out my eyes. I really hope that there is an option for this and only I could not find it.

Thanks in advance!

P.s: I do not want to install any themes/plugins/whatevers to solve this problem, the previous Firefox pdf viewer did not need them.

All Replies (4)

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The developers are aware of the this issue (see issue #12290). The builtin PDF viewer does come with a dark mode which is based on whether or not you are using your operating system (in your case, Windows) in dark mode.

There's some talk about changing the way that the PDF viewer dark mode works, so hopefully it will be addressed in a future version of Firefox.

You can set it to dark mode by changing your computer to dark mode. That can be done by going to the Windows Settings, selecting Personalization, then Colors and changing the Choose your default app mode setting to Dark.

Hope this helps.

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Thank you for your reply. I am not sure the link you have provided is the same issue. It seems to me that change appeared recently, in the update, that installed on the day of me writing the original post, almost a month later than the date of issue#12290 and a month seems like too much time difference.

Your advice does solve the issue of the PDF viewer, but it creates others: the tabs part of the browser changes to black, which I don't like and the Windows windows and other apps also changes to black, which I also don't like. The dark PDF viewer was the default before that update and I would like to have it back, without changing my operating system settings, because it impacts other applications.

I don't think that Firefox should depend on my Windows settings, nor have anything to do with them, nor accessing them, except the truly essential information (which lets be honest dark mode is not). I use Firefox, because I liked the goals the developers set to themselves and because they seems to be open about their work, respecting the privacy of their users and giving back some control over our browsing. Accessing unnecessary information is making me question these things.

I think Firefox should be treated as an independent entity as much as possible, ensuring that updates do not change significantly the appearance of any part of the browser, but show the options to change it by the user, allowing better customization and user experience.

Please make the PDF viewer dark again (or provide a switch/button in the viewer) by default, changing the appearance of every other application on the computer just for the sake of the dark viewer should not be the only solution.

Again, thank you for taking your time to help with my problem :)

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For Firefox 85+ see:

Hi kopaszkukac69, before Firefox 81, the PDF viewer was one theme for everyone, while the new one follows your system preference. If you only want to modify the PDF Viewer, there is a way to do it. It may violate the principle of --

kopaszkukac69 said

P.s: I do not want to install any themes/plugins/whatevers to solve this problem, the previous Firefox pdf viewer did not need them.

-- but then again, you might grow impatient waiting for Firefox to change and decide you are willing to give it a try.

Modified by jscher2000

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In case it's of interest, there is a new (much easier) option in Firefox 85:

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

(2) In the search box in the page, type or paste the new preference name


If this preference was already created and shows a value of 0 or 1, skip to step (4).

(3) On the bar with the bolded preference name, click the radio button next to Number and click the + button to add the preference. Then Firefox should display the new value.

(4) Set the value to **2** for a dark theme (double-click to edit if necessary) and click the blue checkmark button to save the change. (For reference, 0 is automatic -- looks to system theme -- and 1 is Light.)

Screenshot attached for reference. This should affect new or reloaded PDF viewer tabs.