keyboardWillShow fire twice
<p>I'm stuck with problem "keyboardWillShow" fires twice, but the "keyboardWillHide" called once.</p>

<p>Here is <a href="https://github.com/x-hovo-x/KeyboardWillShow.git" rel="noreferrer">an example</a> where I'm printing the keyboard sizes as soon as "keyboardWillShow" fires.
I've also put breakpoint in "viewDidLoad" and the observer registers only once.
I've added two elements "UITextField" and "UITextView" and for both it is the same behaviour.</p>

<p>I'm using iOS 9.2, swift lang., xcode 7</p>

<p>Below my ViewController</p>

<pre><code>class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillShow:"), name: UIKeyboardWillShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("keyboardWillHide:"), name: UIKeyboardWillHideNotification, object: nil)
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func keyboardWillShow(notification: NSNotification) {
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.CGRectValue() {
        print("keyboardWillShow sizes: \(keyboardSize)")
    }

}

func keyboardWillHide(notification: NSNotification) {
    print("HideHideHide")
}

}
</code></pre>

<p><strong>UPDATE</strong></p>

<p>First time it fires once with sizes: 
keyboardWillShow sizes: (0.0, 568.0, 320.0, <strong>253.0</strong>)</p>

<p>for the rest it twice with different sizes:(second y position is changed also the height changed)
keyboardWillShow sizes: (0.0, 568.0, 320.0, <strong>216.0</strong>)
keyboardWillShow sizes: (0.0, <strong>352.0</strong>, 320.0, <strong>216.0</strong>)</p>