Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

If there is still a problem, 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). Did this help?

While you are in safe mode;

Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches.

How to disable Hardware Acceleration {web link}

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content. You can click shield icon for more detail and possibly disable the protection. You can check the Web Console for messages about blocked content.

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop

I had deleted all walmart cookies before posting, but neglected to mention that. I prefer not to delete all cookies except in dire circumstances. Clearing the cache did not help.

The problem does not occur in safe mode.

Disabling hardware acceleration does not solve the problem.

Enhanced tracking protection was previously and remains off for walmart.com.

I have none of the mentioned extensions nor others which block content. I have an ad blocker and a DNS-based malware blocker in my router but disabling them makes no difference.

Can you list your extensions ?

• https://support.mozilla.org/en-US/kb/use-troubleshooting-information-page-fix-firefox

If it works in Safe Mode and in normal mode with all extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) disabled then try to find which extension is causing the problem by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via one of these:

• "3-bar" menu button -> Exit (Power button)
• Windows: File -> Exit
• Mac: Firefox -> Quit Firefox
• Linux: File -> Quit

> Can you list your extensions?

The list from Troubleshooting Information: 1Password X – Password Manager extension 1.20.0 true {d634138d-c276-4fc8-924b-40a0ea21d284} Amazon.com extension 1.1 true amazondotcom@search.mozilla.org Bing extension 1.1 true bing@search.mozilla.org Bypass Paywalls extension 1.7.4 true bypasspaywalls@bypasspaywalls.weebly.com DuckDuckGo extension 1.0 true ddg@search.mozilla.org DuckDuckGo Privacy Essentials extension 2020.7.22 true jid1-ZAdIEUB7XOzOJw@jetpack eBay extension 1.1 true ebay@search.mozilla.org Google extension 1.0 true google@search.mozilla.org ReviewMeta.com Review Analyzer extension 2.5 true FirefoxExtension@ReviewMeta.com Wikipedia (en) extension 1.0 true wikipedia@search.mozilla.org (The heading of the 4th column, which contains all "true," is "Enabled."

The list from Tools::Add-ons shows only these four: 1Password X – Password Manager, Bypass Paywalls, DuckDuckGo Privacy Essentials, and ReviewMeta.com Review Analyzer; all of them enabled. The others listed above must be from their being the default search engine or "One-Click Search Engines" specified in Settings::Search.

And now, the result of the grand extension isolation experiment: the problem occurs only when the DuckDuckGo Privacy Essentials extension is enabled. I am considering this a solution. Some of the functionality of that extension seems to now be in Firefox.

Thanks for your help!