Page field: new hide from navigation option: checkbox could be turn on/off for internal links but not saved

The page field is getting quite confused with the url key field (which is sometimes turn on or off but not hidden) and the new "hide from navigation menu" option.

The former (url key) is not editable on internal links, external links, etc... but is stil visually present. There are no clear indication that this field is not editable (grey out or fully hidden). So as a end-user you click in it and you presume that there is a bug because you can not enter any content.

The latter (new checkbox) is however editable even for internal links. But when you turn it on, save your internal link and reopen your engine, the cross check has disappeared and was not serialized. so if it is only available for direct sub-pages, such an option should only be present on direct sub-page and grey-out/hidden for other options.