Unsupported configuration plain style unsupported in a navigation item

Question

When i try to add a button to a navigation bar, i got this warning:

unsupported configuration plain style unsupported in a navigation item

Concerning the Plain style, i don't find it in interface builder since i moved to Xcode4.2.

EDIT: @Michael: here is what Xcode look like for me:

I have not the arrow to the left, is there any thing missing there?

Answer 1

Is the button you added a "Bar Button Item"?

Answer 2

1. go to the navigation item
2. select the navigation Bar button

3. just change the bar button item in attribute inspector

   style - bordered
   

   and then run the program warning is not showing