Just to be clear you are able to create the menus with MenuWriter but are just unable to edit them, correct?
Please post back and let us know if this resolves the issue, if not I will open a ticket for you so we can look into the matter further.
I posted another picture to show you that the Invisible Elements option was also already checked in the View menu. Yes, I can create the menus with MenuWriter, but I am unabel to edit them.
( header_css_menu_writer.php )