Hello

You can try. Customize Firefox using policies.json. https://support.mozilla.org/en-US/kb/customizing-firefox-using-policiesjson

The Enterprise Policy Generator https://addons.mozilla.org/firefox/addon/enterprise-policy-generator helps to create the configuration file.

Erratum code, Errare humanum est.

{ "policies": { "Preferences": { "browser.tabs.hoverPreview.enabled": { "Status": "locked", "Type": "boolean", "Value": false } } } }

Restart Firefox. Your browser is being managed by your organization. Firefox policies affect all profiles.

Thank you for the reply. I did observe this issue for a few weeks now, and it did not reappear. It remains a mystery, but as long the setting is not reverted back again, that's fine by me.

Note: There are no organization policies. This is a regular "home-user" profile.

Resolved. Solution unknown.