Firefox 55.0.1 on FreeBSD 11.1

T170055 ?

On which wiki are you experiencing this? This looks like a duplicate of T177482, which in turn has to do with T177478.

On which wiki are you experiencing this?

On main Wikipedia site.

"Automatically enable all new beta features" is at fault because it was "on".

The right fix: When "Automatically enable all new beta features" is "on", all individual checkboxes should be set to "on" and disabled so that the user shouldn't be able to change them. Alternatively, "Automatically enable all new beta features" should be unchecked when the user disables any of the features.

What mean?

main Wikipedia site

https://en.wikipedia.org/

In T177508#3661412, @Yurivict wrote:

https://en.wikipedia.org/

OK. en.wikipedia.org is not main wikipedia site.. Main wikipedia site is wikipedia.org

Just to clarify, you are saying that:

1. Automatically enable all new beta features checkbox is enabled
2. "Wikitext syntax highlighting" checkbox is checked
3. You want to disable "Wikitext syntax highlighting"
4. You untick "Wikitext syntax highlighting" and hit save
5. When the page reloads "Wikitext syntax highlighting" is still checked.

And that you would expect one of the below to actually happen:

1. When "Automatically enable all new beta features checkbox" is enabled, all checkboxes for individual beta features are disabled
2. When "Automatically enable all new beta features checkbox" is enabled, unchecking a beta feature and saving actually disabled and unchecks that beta feature (also unchecking the Automatically enable all new beta features checkbox option)

All makes sense from my point of view, although I think the part I have left in brackets is probably optional, as the "Automatically enable all new beta features" only talks about NEW features.

I dont think this is related to T177482, as as far as I can tell the code causing that issue is not yet deployed.