How to display the "assistant editor"?

Question

http://developer.apple.com/library/ios/#DOCUMENTATION/iPhone/Conceptual/iPhone101/Articles/05_ConfiguringView.html

• In Xcode, select the view manager nib file (MyViewController.xib).
• Display the assistant editor.
• Ensure that the Assistant displays the view manager header file (MyViewController.h).
• Control the drag from the button in the nib file to the method declaration area in the header file.

How to do step 2?

How to display the "Assistant Editor"?

Answer 1

It is exclusively for Xcode 4:

Answer 2

In xcode 6

This is the second button with two circles.

Answer 3

In Xcode 6.2, it seems like they've changed the icons again. I had trouble finding it, but I didn’t understand where the buttons were, while the dumb old man trying to pick up iOS thought I was lacking in presentation, so I publish this for any passerby who needs some kind of visual confirmation.

To be fair, I was looking for something based on some instructions that I read that referred to two circles, and it never occurred to me that two circles meant a split view editor / assistant, and only after that I understood, understood did I that the costume was a reference to the assistant assistant assistant: "D