yes as soon I debug an important rights access issue on my xwiki :-/
Done! A user set access rights on pages & Children but without using groups 
It is not easy to view that rights are set by user, in this case: we must edit WebPreference in object mode
Thanks @Pbas. Shouldn’t you also specify the version of XWiki? Are you sure the problem you mention are true for all versions of XWiki?
I add xwiki version. I tested with 2 xwiki version but for one issue it seem that with http://twitter.com/ I have sort of same issue: https://github.com/gorhill/uBlock/issues/3711
FYI ublock close my issue because it is FF issue: https://bugzilla.mozilla.org/show_bug.cgi?id=1401516
I’m not agree bc FF working well without ublock, but it doesn’t matter.
Probably this issue:https://developer.mozilla.org/en-US/docs/Archive/Add-ons/Working_with_multiprocess_Firefox
Starting from Firefox 53, no new legacy add-ons will be accepted on addons.mozilla.org (AMO) for desktop Firefox and Firefox for Android.
Starting from Firefox 57, only extensions developed using WebExtensions APIs will be supported on Desktop Firefox and Firefox for Android.