How to display "the" Assistant Editor?

Question

https://web.archive.org/web/20110604185120/http://developer.apple.com/library/ios/documentation/iphone/conceptual/iPhone101/Articles/05_ConfiguringView.html

To add an action for the button . . .

1. In Xcode, select the view controller’s nib file (MyViewController.xib).
2. Display the Assistant editor.
3. Make sure Assistant displays the view controller’s header file (MyViewController.h).
4. Control 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's exclusive to Xcode 4:

Answer 2

In Xcode 6

It is the second button with two circles.

Answer 3

EDIT: As of the latest version of Xcode this has changed.

In XCode 6.2 it seems they've changed the icons again. I was having trouble finding it but I didn't realize where the buttons were until the dumb old me trying to pick up iOS thought I was missing a view, so here I am posting this for any passerby who needs some visual confirmation.

To be fair, I was looking for something based of some instructions I had read that referenced the two circles, and it didn't occur to me that two circles meant a split view / assistant editor, and not until after finding this post and figuring it out did I realize a suit was a reference to a butler AKA assistant :D