Do you see locked prefs about cookies on the the about:config page?

• https://support.mozilla.org/en-US/kb/about-config-editor-firefox

checked about:config but not knowing exactly what to look for, I searched for anything with cookies.

the closest was services.sync.prefs.sync.pref.privacy.disable_button.cookie_exceptions but changing that and restarting FF did nothing.

searching for anything with disable_button showed nothing.

starting FF in troubleshoot mode did make them appear and they work. I would prefer I did not have to do this.

I thought maybe my local windows domain was somehow doing something. I downloaded the FF group policies and nothing was enabled that would block it.

disabling all my add ons and restarting did nothing.

Go to about:config and change toolkit.legacyUserProfileCustomizations.stylesheets to false then restart the browser.

Ah, I missed that you are using userChrome.css/userContent.css, but I don't know why you would have CSS code to hide those buttons. This could be a problem with the dark theme that you use and that the buttons are there but not visible. Is that dark theme done via CSS code in userChrome.css userContent.css?

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the Default System theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

• https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Go to about:config and change toolkit.legacyUserProfileCustomizations.stylesheets to false then restart the browser.

well that's annoying, it worked but then firefox looked like crap. I had to turn it back on again. there is something in preferences_alternative_appearance.css that was causing it. preferences_alternative_appearance_aero.css and preferences_alternative_appearance_v2.css do not have the problem but make my firefox settings unreadable. the problems seems to have shown up in the last month or 2 as I have been using the userchrome.css for a couple years and could access the buttons before.

so I disabled preferences_alternative_appearance.css and now the buttons are back, somehow in doing that "Delete cookies and site data when Firefox is closed" got checked and undid all my website settings sigh™.

oh well at least the problems has been fixed.

I do not remember exactly what or why I had preferences_alternative_appearance.css (I set it up over 2 years ago) I looked through it and could not find a setting that turned off those buttons. disabling preferences_alternative_appearance.css didn't seem to change the look of the settings page except the missing buttons reappeared. either way I don't seem to need it.

as I said this issue appeared in the last few months.