Hi pascal12, try turning off disk caching to see whether that helps:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

(2) In the search box in the page, type or paste cache and pause while the list is filtered

(3) Double-click the browser.cache.disk.enable preference to switch the value from true to false

About this part --

Also when i save a form 50% of time it don't save values.

-- I'm not sure what you mean by saving the form. Do you mean when you submit the form, it isn't getting submitted successfully? That seems like a different problem, probably not related to excess caching.

Thanks for help, i disabled cache and i will test like that.

For other part, y it seems form saving work bad ...

I have other problems like image list in joomla CMS not refreshed or empty. Too much problems with this new cache system ... I have to switch to Chrome for work.

Please do more intensive tests before publishing such changes. it totally ruin efforts to bring back Firefox to front ... Sad !

Hello, any news about this bug ?

Yes i call it a bug cause many of our customers working with Firefox have the same problem.

Working in websites backoffice (Joomla, Prestashop, etc ...) is now almost impossible ! We have to use CTRL-F5 each time we load or relaod a page ...

Is Mozilla technical team aware of this problem ??

On some page (mostly with ajax) we have to empty cache + use CTRL F5 to get right version ...

Hi pascal12, the developers are aware that style sheets are cached more persistently, and that has side effects primarily for developers. If users cannot see content changes in their CMS due to aggressive caching, please file a separate bug for that:

• https://bugzilla.mozilla.org/
• https://developer.mozilla.org/docs/Mozilla/QA/Bug_writing_guidelines

The problem go much more far than style sheets cached too persistantly ... It is the same for lot of other things on page including form fields, or session elements (like informations displayed when logged in that still display when logged off).

And it's not only for developpers. All my customers using firefox to manage their sites called me cause they have strange behaviours ... And now all use Chrome ... Very bad move.

You can file a bug as I mentioned earlier. The only CMS I use is WordPress, so I cannot test Joomla, etc.

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

And it's not only for developpers. All my customers using firefox to manage their sites called me cause they have strange behaviours ... And now all use Chrome ... Very bad move.

Yes, we have tha same problem, we send emails to our all customers to not use firefox for administering their websites!

When I tested whether Firefox 80 and Chrome 85 reload cached style sheets when I press F5, I got the same results on this test page:

https://www.jeffersonscher.com/csscache/index.html (check time stamps after pressing F5)

Maybe there is a different combination of headers I haven't tested that will show a difference.

On our side we have reviewed and modified cache policy on our servers.

Nginx config was changed from this :

map $sent_http_content_type $expires {

   default                    31d;
   text/css                   90d;
   text/js                    120d;
   application/javascript     120d;
   ~image/                    90d;

}

To this :

map $sent_http_content_type $expires {

   default                    off;
   text/html                  epoch;
   text/css                   max;
   text/js                    max;
   application/javascript     max;
   ~image/                    max;

}

It seems to solve the problem ... BUT now we have no more HTML elements cached by browser :/

For developers, I created an extension you can use to temporarily prevent caching of CSS files from your own servers (or any servers, you create the host list and set the host permissions):

• https://addons.mozilla.org/firefox/addon/no-cache-no-store-for-css/
• https://github.com/jscher2000/No-Cache-No-Store-Extension

This doesn't help your site visitors, who will still have old CSS files cached for a while. I notice in some CMS the href in the stylesheet link tag has a version number argument (this may be part of a WordPress theme, for example):

<link rel="stylesheet" href="style.css?ver=3.1">

Maybe that could be a workaround to address the end user situation once changes are final and roll out to production.