Strange, which version of Mozilla are you using?

I just updated today to 66.0.1. But the problem existed before the update.

It would help to know what the addons are.

If they are extensions, they should be listed on the Troubleshooting Information page. Either:

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

Scroll down past "Application Basics" and "Firefox Features" to "Extensions". Anything here? They should also show up on the Add-ons page. If they don't, hmm, that's strange.

WestEnd said

It would help to know what the addons are.

They are noscript, adblock plus and video downloader. I can't give exact info as that is what I was trying to find on the addons page.

If they are extensions, they should be listed on the Troubleshooting Information page. Either:

• "3-bar" menu button > "?" Help > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

Scroll down past "Application Basics" and "Firefox Features" to "Extensions". Anything here? They should also show up on the Add-ons page. If they don't, hmm, that's strange.

Adblock Plus - free ad blocker 3.5 true {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d} Easy Youtube Video Downloader Express 14.3 true {b9acf540-acba-11e1-8ccb-001fd0e08bd4} New Tab Override 14.2.0 true newtaboverride@agenedia.com NoScript 10.2.5 true {73a6fe31-595d-460b-a920-fcc0f8843232} Open in Chrome 0.2.4 true {086f665e-6a55-4107-9147-f9a14e72b137} Video DownloadHelper 7.3.5 true {b9db16a4-6edc-47ec-a1f4-b86292ed211d} Classic Theme Restorer 1.7.3.4 false ClassicThemeRestorer@ArisT2Noia4dev Open In Chrome 1.6.3 false openinchrome@griffeltavla.wordpress.comjscher2000 said

Some of them I think are no longer active and probably should be deleted but how if I can't see them?

Hmm, I'm puzzled why they don't show up on the Add-ons page, Extensions panel. If you want to do some weeding out, you could try Firefox's Safe Mode.

In its Safe Mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is not running: Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.)

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" Help button > Restart with Add-ons Disabled
• (menu bar) Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement with the Add-ons page?

I safe mode they show up. But that reminded me that I am using a modified chrome.css file to get my tabs back where they belong below the address bar. Could that be the issue?

FYI running windows 7 PC

It's hard to see how a userChrome.css rule directed to the tabs bar could affect the Add-ons page. Did you just update your rules for Firefox 66 or has the file been stable since Firefox 65?

Do you have a userContent.css file? That is more likely to affect the Add-ons page.

The file has been there since begin of FEB. I found it posted after the update to 65 that killed the tabs.

Usercontent was the issue. I renamed it and now they are there. I don't remember why that file was added. Perhaps the first time the tabs were moved. I think I wanted classic theme back.

jdevlin said

Usercontent was the issue. I renamed it and now they are there. I don't remember why that file was added. Perhaps the first time the tabs were moved. I think I wanted classic theme back.

Okay, if you notice something isn't modified the way you expected, then we can go back into that file and see whether there are any comments explaining what those rules were supposed to do.

Is there somewhere I read up about what the rules there mean? I am somewhat familiar with programming just not this system.

For now everything looks good so I am just leaving it disabled.

Thanks

jdevlin said

Is there somewhere I read up about what the rules there mean? I am somewhat familiar with programming just not this system.

How long do you have? Most CSS rules start with a selector that identifies the part of the page that the rule styles. This is the first problem because large parts of Firefox's internal pages and user interface are not written in standard HTML, but something called XUL. This means more research for you to interpret the rules.

Once you've figured out what the selectors affect, then there are the properties the rule modifies. That may be more straightforward.

Rules in userContent.css may also have some scope limitations. For example:

@-moz-document url-prefix(about:addons) {}

around a rule would restrict its effect to the Addons page. At least in theory. The absence of such scopes can modify everything you load in a tab that has a match to the selectors. Which can have unintended consequences.

Thanks I found this page and will do some reading to see if can understand what the commands were for in the file that gave the problem.

https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XUL

To get an idea of the XUL for the overall user interface, try this internal file (need to paste to the address bar and load, the link doesn't work):

view-source:chrome://browser/content/browser.xul

Or for the Add-ons page:

view-source:chrome://mozapps/content/extensions/extensions.xul