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I accidentally changed my background to black and now cannot see anything on screen. How do I undo?

  • 23 respostas
  • 1 has this problem
  • 60 views
  • Last reply by Jay Simkin

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Text in white on white so I went to change font color to black and ended up changing background as well. Now everything is black so I can't see menus to undo. There was no 'Undo' option. Is there a workaround to return font/background color to default?

Text in white on white so I went to change font color to black and ended up changing background as well. Now everything is black so I can't see menus to undo. There was no 'Undo' option. Is there a workaround to return font/background color to default?

Chosen solution

Thanks for your suggestions. I went onto Safari and found a suggestion to use the upper right menu and reset to default. That did the trick and I didn't lose any saved bookmarks or other info. I agree that it would be helpful if you couldn't cause the problem in the first place. Or have a 'test' that defaults back to where you were after a few seconds - maybe then a second prompt to execute the change.

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All Replies (20)

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Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh).

See if you can change things back from here.

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You can try to edit prefs.js in the profile folder and remove the corresponding lines or create a user.js file.

user_pref("browser.display.background_color", "#FFFFFF");
user_pref("browser.display.foreground_color", "#000000");

You can find the profile folder in this hidden location in AppData\Roaming.

  • %AppData%\Mozilla\Firefox\Profiles\

Open the folder with the random name: xxxxxxxx.default

Use a plain text editor to create a new text file and paste the above posted user_pref() lines in the file. Make sure you select "All files" in the dialog to save the file in the text editor as user.js using "Save File as".

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Maybe someone should file a bug to make it impossible to assign the identical color to both text and background through the Colors dialog. You could still do it in about:config; it's hard to protect users there!

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To do this in about:config you would have to add event listeners to both these prefs and do a test to contrast difference between the two settings. There are functions that can achieve this and background and foreground can be swapped in some cases, so this could be extended to include this situation.

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You can remove the user.js file once you are done because otherwise you won't be able to change these colors permanently (user.js is parsed each time you start Firefox).

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Chosen Solution

Thanks for your suggestions. I went onto Safari and found a suggestion to use the upper right menu and reset to default. That did the trick and I didn't lose any saved bookmarks or other info. I agree that it would be helpful if you couldn't cause the problem in the first place. Or have a 'test' that defaults back to where you were after a few seconds - maybe then a second prompt to execute the change.

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Were (are) you using an inverted High Contrast theme on your Mac?

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All of these proposed solutions involve editing files, the locations of which I could not describe, even if water-boarded. And, even if I could find them, I hesitate to make changes, when a single-symbol error could do great damage, that I'd not know how to fix.

I used to be able to choose the display colors for links, visited and unvisited. After I installed Version 70, I am forced to accept a blue-violet for unvisited links and a fluorescent lime-green for visited links. Why did this revision remove an end-user's capacity to choose the display color for links. Why would anyone - in upgrading Firefox - tamper with something that worked perfectly?

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Hi Jay Simkin

Did you check the default colors ?

  • Options/Preferences -> General: Fonts & Colors -> Colors
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Thanks for your reply. Yes.

I even chose "new" colors for visited and unvisited links - "new" meaning colors I'd never used - to see if I could over-ride what seem to be embedded (hard-coded) colors (blue violet and fluorescent lime green). I cannot change these embedded colors, which only appeared after I installed Version 70.0.

Another change - not for the better - is that the capacity to display stored passwords seems to be have been removed. Being able to view stored passwords was hugely helpful and saved me having to request a password "reminder". With no reason or warning, "viewed stored passwords" was gone!

It would be won-der-ful if changes were announced two weeks before they are made. That would allow some time for feedback, before the changes take effect.

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What you specify for colors in Options/Preferences is only used when a website doesn't specify their own colors. If you would disable website colors then this affects background images and you might not notice buttons that are styled with a background image.

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Prior to V70, I was able to control the color of visited and unvisited links. So, in my e-mail program, in the inbox, the subject was always in white. Now it is in blue-violent. If I open the message, then the subject line content becomes fluorescent lime green. This never happened prior to V70. It does not happen in I.E. 11, most current version.

Your reference to "buttons" seems not relevant, as links may be identified by color or by underlining.

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Jay Simkin said

So, in my e-mail program, in the inbox, the subject was always in white. Now it is in blue-violent. If I open the message, then the subject line content becomes fluorescent lime green. This never happened prior to V70. It does not happen in I.E. 11, most current version.

What color are the links in IE? Does Firefox seem to be inverting the page to a dark mode or is the link color the only difference?

Jay Simkin said

Another change - not for the better - is that the capacity to display stored passwords seems to be have been removed. Being able to view stored passwords was hugely helpful and saved me having to request a password "reminder". With no reason or warning, "viewed stored passwords" was gone!

On the Logins page, there is a ••••• line for the passwords with an "eye" icon to make it visible. If you use a Master Password, you need to enter the Master Password after clicking the "eye". Each. Time. (I realize it gets old, this might change in a future update.)

More info: Password Manager - Remember, delete and edit logins and passwords in Firefox

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Thanks for your continued help! The links in IE are white, as always. Firefox (V70) respects my page background color choice - always black - and allows text I enter to appear in white. Sadly, not so for links.

My screen color set-up mimicks that used by air traffic controllers: colored or white symbols on a black background. This minimizes eye-strain.

Thanks also for your comments anent passwords. I don't use a master password.

As to the "eye" icon, I can't see it (pun intended): it does not appear on the screen, even if I use Microsoft Standard colors, i.e., medium gray letters on a pale gray - supposed to be "white" - background.

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Hi Jay Simkin, yes, forcing white on black does not work well with the Logins page (comparison attached).

Are you a patient person? You could look at setting up a more sophisticated color override using ShadowFox (instead of using override...always): https://overdodactyl.github.io/ShadowFox/

jscher2000 - Support Volunteer modificouno o

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I have no idea how many things "ShadowFox" might cause not to work, that now work smoothly. I try to avoid "night jumps, in bad weather".

I doubt anyone set out to force on me - and presumably others - specific colors for visited and unvisited links. This I suspect the change was inadvertent.

Can you please suggest how to get this change reversed and so getting restored the capacity to specify the color of visited and unvisited links?

It is hard for me to imagine that there's any benefit to anyone from this color choice limitation.

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Jay Simkin said

Can you please suggest how to get this change reversed and so getting restored the capacity to specify the color of visited and unvisited links?

The old settings still work for me on simple sites, but I use a normal Windows theme. Do you use a "High Contrast" theme? Or a dark theme?

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For at least 30 years, I've used a black screen background, with white letters. This mimics air traffic controllers' screens: white and colored symbols on a black background. This set-up limits eye-strain for folks who must stare at their screen for two-hours at a stretch. Eye-fatigue for them puts lives at risk.

While almost all computer screens can generate a true (jet) black, most cannot provide a true white. So the normal Windows theme uses a gray-white background, against which nominally black letters become a dark gray. This low-contrast color scheme is akin to staring at a fluorescent bulb. I see no reason to abuse my eyes: they are not replaceable!

Thus, I think I have a "high contrast" scheme. I do not know what is a "dark theme", as used in this context.

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Hi Jay Simkin, Windows has various themes. Firefox will attempt to mimic some features of High Contrast themes. This is not new, but Firefox may not let you modify certain colors when you use a High Contrast theme, so that is why I asked.


What is new in Firefox 70 is that websites can adapt colors based on whether Firefox characterizes your system theme as "dark." So that's a new complication, although I don't know if it makes any difference on Windows, it was added for MacOS users.

Here are your options for this hidden setting if you want to test:

(0) Select and copy this preference name:

ui.systemUsesDarkTheme

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

(2) In the search box above the list, type dark and pause while the list is filtered

(3) Right-click in the blank area and choose New, then Integer

(4) Paste the preference name you copied earlier and click OK

(5) Type the value you prefer Firefox to report to the page and click OK

  • 0 => Light
  • 1 => Dark
  • 2 => No Preference

To try a different value, double-click the preference and modify the value then click OK.

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Dear JScher, I am not - and have never been - a software engineer. Thus, I do not modify programs by making changes, the impacts of which I cannot assess or undo, should the impacts be adverse. I will make changes using menus provided by the software engineers. But I will not go into "source code" or similar files, and alter them. I simply lack the knowledge to do this.

This matter is simple. Someone changed Firefox, such that functionality long present was removed. That person should take ownership of this problem. It is not for me to solve a problem that I did not cause. It is even less for me to risk all sorts of collateral damage, trying to fix a problem that I lack the knowledge to fix.

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