After just installing Odoo 11 yestaerday, I've watched this:
https://www.youtube.com/watch?v=6OeDxrsvwtc
and this:
https://www.youtube.com/watch?v=DeEOm9xGDxo
But following those steps, I still don't see any "Show full accounting features" in developer mode.
please provide screen shot of you user form view(developer mode activated).