Assistant Editor shows different "ViewController.swift" file than the one that Main Editor shows?
<p>The source code shown in the <em>Assistant Editor</em> for "ViewController.swift" is different than source code shown in <em>Main Editor</em> for "ViewController.swift".</p>

<p>"ViewController.swift" in <code>Main Editor</code>:</p>

<pre><code>//  ViewController.swift
//  FoodTracker

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {
    // MARK: Properties
    @IBOutlet weak var nameTextField: UITextField!
    @IBOutlet weak var mealNameLabel: UILabel!
    @IBOutlet weak var mainButton: UIButton!

    override func viewDidLoad() {
        super.viewDidLoad()
        nameTextField.delegate = self
    }

    // MARK: UITextFieldDelegate
    func textFieldShouldReturn(textField: UITextField) -&gt; Bool {
        textField.resignFirstResponder()
        return true
    }

    func textFieldDidEndEditing(textField: UITextField) {
        mealNameLabel.text = textField.text
    }

    // MARK: Actions
    @IBAction func setDefaultLabelText(sender: UIButton) {
        mealNameLabel.text = "DEFAULT text"
        // mainButton.tintColor = UIColor.darkTextColor()    
    } 
}
</code></pre>

<p>"ViewController.swift" in <code>Assistant Editor</code>:    </p>

<pre><code>//
//  ViewController.swift
//  FoodTracker
import UIKit

internal class ViewController : UIViewController, UITextFieldDelegate {

    @IBOutlet weak internal var nameTextField: UITextField!
    @IBOutlet weak internal var mealNameLabel: UILabel!
    @IBOutlet weak var mainButton: UIButton!

    override internal func viewDidLoad()

    internal func textFieldShouldReturn(textField: UITextField) -&gt; &lt;&lt;error type&gt;&gt;

    internal func textFieldDidEndEditing(textField: UITextField) -&gt; &lt;&lt;error type&gt;&gt;

    @IBAction internal func setDefaultLabelText(sender: UIButton) -&gt; &lt;&lt;error type&gt;&gt;
}
</code></pre>

<p>So, those are completely different different files, but have the same name. The one in the <code>Assistant Editor</code> is the <em>interface</em> while the file shown in the <code>Main Editor</code> is the implementation of the interface, right?</p>

<p>That seems a little weird, but the interface and implementing class have the same name? When I'm working in Xcode I need to be aware that sometimes two files can (often?) have the same name?</p>