TYPO3 Core

Most probably related to https://github.com/TYPO3/TYPO3.CMS/commit/b5ef37599d

I had a bad filling when reviewing #91083 https://review.typo3.org/c/Packages/TYPO3.CMS/+/64491 but I removed my -1 vote because I had no time to involve, neither Susanne Moog, nor Chris Müller.

The clear_preview() call that was removed WAS obsiously important.
I thought the issue is more a middleware priority issue (see my comment on the review): the admin panel middleware should run after the frontend middleware

I have the same behaviour in v10.4.8. After Shift+Reload with active Admin Panel and activated "Show hidden records" the hidden elements are delivered also to website visitors.

1. The editor has "Show hidden records" deactivated.
2. She activated the "Show hidden records" options.
3. The page is shown with no hidden elements (from cache, I assume).
4. Shift+Reload builds the page with hidden elements.
5. As a normal website user (not logged-in) I see now also the hidden elements from that page.

With activated "No caching" option this behaviour was not observed.

@Daniel Hinderink Rémy

It seems to me the problem is that the page is cached (as viewed by the BE user). As Chris pointed out, the problem does not occur if "No caching" is activated.

The adminpanel view (or logged in view) and not logged in view should have a different cache entry. This does not seem to be the case.

BTW, we had a similar (or the same) problem quite some time ago, where pages with Fluid debug output (there is also an option for that in adminpanel) were also visible in non-logged in view.

see #85087 ("Prevent Admin Panel Fluid Debug View from being cached")

I cannot reproduce problem with Fluid debug output (in 9.5.22).

I can still reproduce problem with hidden elements (in 9.5.22).

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/66156

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/66156

Patch set 1 for branch 10.4 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/66192

No fix for version 9.5 ?

I added a comment to patch https://review.typo3.org/c/Packages/TYPO3.CMS/+/66156 and raised issue in Slack. So I would recommend to wait patiently for now, until someone responds or it is backported.

There might have been problems backporting (sometimes there are conflicts and things done differently).