Let’s do a full clean re-install;

Download Firefox For All languages And Systems {web link}

Save the file. Then Close Firefox.

Using your file browser, open the Programs Folder on your computer.

Windows: C:\Program Files C:\Program Files (x86)

Mac: Open the "Applications" folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac

Linux: Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux

If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Look for, and remove any Mozilla or Firefox program folders. Do not remove the Mozilla Thunderbird folder if there is one.

Do Not remove any profile folders.

After rebooting the computer, run a registry scanner if you have one. Then run the installer. +++++++++++++++++++++++++++ If there is a problem, start your Computer in safe mode and try again.

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia

So...

I deleted the Mozilla Maintenance Service folder and an old Mozilla Firefox 60 folder out of C:\Program Files (x86), and deleted the current (61.0.1) Firefox folder out of C:\Program Files, leaving Thunderbird as the only Mozilla folder in the Program Files folders. I rebooted, then ran CCleaner's Registry Cleaner, letting it fix everything it found (mostly references to Firefox). Rebooted again. Ran Firefox Setup 61.0.1.exe. Started Firefox, which clearly found my profile as it started up with extensions, bookmarks etc.

The problem still exists.

Some further details:

The problem always manifests on first opening of about:preferences in a Firefox session. The wording is fine in the column of the sections on the left.

If I keep clicking to move between the different sections, and fully scroll each sections up and down quickly, eventually the wording appears first in the Home Firefox Home Content section (but not the New Windows and Tabs part of the Home section above it). With more clicking between sections and scrolling within them, eventually the wording appears in the others.

Once the wording has appeared, it stays on further Options openings in the same FF session.

I tried turning off Use Hardware Acceleration. No difference. I tried setting Firefox to use my NVIDIA GeForce card instead of the internal Intel graphics it uses by default. No difference.

I mjust say that I am especially puzzled by the way the text appears eventually on clicking and scrolling on the page. Simply not working would be easier to diagnose.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Starting in Safe Mode, the problem is NOT there,

For normal starts, I have tried disabling Hardware Acceleration - problem still there. I have gone through disabling each add-on in turn - problem still there. I discovered an oddity in the Themes section in that all 3 - default, dark and light - were showing as disabled; but the problem was still there when I enabled default (which is marked with a yellow Legacy sign, which is strange), which didn't change the FF window at all, and also when I tried enabling light and dark themes.

I have discovered something new. What I said above about the text finally appearing after I switch many times between the different sections of the Options window and scroll them all is incorrect. In fact what is happening is that the text appears 35 seconds after I open the Option window, even if I open it and then do absolutely nothing after clicking on the Options button. It wasn't my switching sections and scrolling triggering the text appearing - it was just the 35 seconds from opening. This timing has been consistent over several runs loading FF, clicking the Options button while starting a timer, and stopping the timer when the text appears.

What on Earth starts on Options tab open, and finishes 35 seconds later? And I will again emphasise that this ONLY happens in the about:preferences page. I have had no such thing happen on any other page, whether an about: or an external page.

Sounds like a script problem. Did you switch to the default theme?

You can check the Web Console (Tools -> Web Developer) for messages.

• https://developer.mozilla.org/en/Tools/Web_Console

FredMcD said

Sounds like a script problem. Did you switch to the default theme?

I thought I was using the default theme as I have never changed it. As mentioned above, when I went to check (after looking at the list of what Safe Mode changes) I found all three of the themes FF installs itself, default, dark and light, ALL were marked as disabled, although it had been displaying as if Default theme was selected. Since then I have enabled the Default theme (no visible change), then also tried switching to the Dark and Light themes, and finally back to Default. None of it has made any difference to the problem, which occurs whichever theme is enabled.

I do notice that the Default theme, if I click the More button for details, has the Legacy (black text in yellow box) showing. Is that correct? But if that were the problem, it should be OK with Dark or Light themes enabled (which are not marked Legacy) instead. but it isn't.

As well as going through disabling each extension in turn, I've also tried disabling ALL my extensions together. Problem still shows.

You can check for problems with preferences.

• delete possible user.js and numbered prefs-##.js files and rename/remove the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases
• http://kb.mozillazine.org/preferences_not_saved
• http://kb.mozillazine.org/resetting_preferences

cor-el said

You can check the Web Console (Tools -> Web Developer) for messages.

• https://developer.mozilla.org/en/Tools/Web_Console

Er ...

Back in the 90s I could write simple web pages in HTML in a text editor, but I've never learned CSS or more recent web technologies. I've looked in the web console, but I don't know what I'm looking for, don't understand most of what it is showing, and nothing jumps out at me.

When I start the about:preferences page, the left side with the list of sections is present, with the clickable section names. All the section pages have all the tick boxes, and ticked or not correctly; they have all the drop-downs marked with choices, like the font name and size, displaying within the drop-down box outlines as normal. The line separators are present, and the rectangular buttons are there, but the buttons do not have the text of the names on them. The layout is exactly what it should be - it is just that the text that is the section headings, saying what a tick box is, labels on the buttons is not visible for 35 sections.

The problem is clearly not that the layout cannot be found, because everything is laid out correctly - when the text appears it doesn't shunt the buttons, tick-boxes etc around, because the page is formatted correctly from opening. It's also clearly not that it can't access my chosen options, because all the tick-boxes, drop-downs etc are correct from opening. Nothing changes when the text appears after 35 seconds other than the text appearing in what were up until then blank areas.

This is just weird.

cor-el said

You can check for problems with preferences.

• delete possible user.js and numbered prefs-##.js files and rename/remove the prefs.js file to reset all prefs to the default value including prefs set via user.js and prefs that are no longer supported in current Firefox releases
• http://kb.mozillazine.org/preferences_not_saved
• http://kb.mozillazine.org/resetting_preferences

Oh ... hell.

No user.js. No prefs-##.js.

I renamed prefs.js. Started FF, problem with Options/about:preferences still there.

Quit. Deleted the new prefs.js, renamed the old one back to prefs.js. Now I've lost my extension toolbar buttons. The spaces for them are there, with the few native FF toolbar buttons showing normally in the usual places between the now blanlk extension buttons; mouse-over still gives name of exgtension button, but no icons and clicking them does nothing or opens an empty titchy panel.

Having to wait 35 seconds for about:preference panes to show text is annoying. Having non-functioning extension toolbar buttons is a disaster.

You can click the Restore Defaults button on the Customize palette page to restore missing toolbar buttons.

cor-el said

You can click the Restore Defaults button on the Customize palette page to restore missing toolbar buttons.

The buttons were not missing. The icons on the buttons were missing, and the functions of the 13 extensions with buttons, and the other 10 extensions that don't have toolbar buttons were missing. All extensions had ceased working including all the ones without toolbar buttons despite all still being listed and enabled.

Disabling then re-enabling did not help. However, I then tried uninstalling and reinstalling two of the extensions that don't have any configuration options (some have a lot of options), and their button icons and functions were restored. After that and then quitting and restarting Firefox, all the 13 button icons and 23 extension functions were back, still properly configured (unlike after quitting and restarting before uninstalling/reinstalling any of them).

So the panic about my extensions is over. But the original problem still remains. I suppose I don't open about:preferences that often, so waiting 35 seconds for the writing to appear is bearable, if annoying. (And at least I now know it is just a wait of 35 seconds, not some sequence of switching panels and scrolling that I couldn't figure out.)

Hm. So it's not any of the extensions. It's not any of the prefs in prefs.js. I've also checked it's not a hold up waiting to Sync, or getting a figure on the amount of disc space used for cookies, site data and cache, or checking if there's an update (the results of all those appear immediately, not only after the 35 second wait). And it's not using hardware acceleration or not. The only odd thing I've found is the 'legacy' tag on the Default theme ... but the problem's still there when using the other (not marked as legacy) themes that come with the FF install.

And while I don't understand (so could be missing something significant) all the stuff in the web console, the only 'error' I find is in the Debugger 'XStringBundle' tab (whatever XStringBundle is), where it says: Error loading this URI: Could not load the source for XStringBundle. [Exception... "Failed to open input source 'file:///'" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: resource://devtools/shared/base-loader.js -> resource://devtools/shared/DevToolsUtils.js :: mainThreadFetch :: line 645" data: yes] Stack: mainThreadFetch@resource://devtools/shared/base-loader.js -> resource://devtools/shared/DevToolsUtils.js:645:5 _getSourceText/<@resource://devtools/shared/base-loader.js -> resource://devtools/server/actors/source.js:410:27 Line: 645, column: 0

But if I then reload about:preferences after the text has appeared, that same web console debugger error message appears again even though the text appeared immediately (as it does every time that session after once waiting the 35 seconds for it to appear first time that session). So I don't think this is relevant.

Sounds that extensions.json might have been corrupted and that uninstalling and reinstalling extensions and a restart fixed this file.

Possibly.

However, that just gets me back to where I was. The original problem remains. Unlike all the hundreds (or likely thousands) of other http: https: and about: pages I've visited since installing FF61, about:preferences, on first load in a session, shows the side panel fine, and all the graphic elements, tickboxes, lines, radio buttons, other button outlines and dropdowns immediately in the main panels, all with the correct choices showing, but doesn't show the titles, captions, explanatory text or button label text for 35 seconds (but does show the text where chosen in a dropdown list, or e.g. in the big search providers box).

Guess I'm waiting for someone who understands the details of the page rendering sequence to pick out which phase is the hold up adn therefore where the problem must be.