Problem editing large menus - 200 odd items 403 error
OK i have done some more trial and error on this.
Apart from the browser specific issues above, the problem seems to be that drag and drop to introduce a new option does not allow saving when either of the "Save Option" buttons are clicked.
If you create a new bare bones option using export / import you can then edit and save correctly using the "i" button and then the "Save" button at the bottom of that entry form.
Rod