MikeF wrote
When I look at the tabs, there is text there. But all it says is [unknown link type]. There's not actually a tab, just the text.
That's because there is no actionlink named "add" and the function just returns an error message and no link. Inserting an input box at this place and make it look nice will definitely require some CSS customizations of the template itself.
I don't know much about the addnewpage plugin maybe you could just add the code to the main navigation of your template (in case you've created one already).