UIPickerView showing empty grey box Swift

I haven't a whole lot of code, so I might as well copy it here.

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource{

    var buildings = ["BankBuilding", "Cinema" , "CornerShop", "Greg's House"]

    @IBOutlet weak var buildText: UITextField!

    var buildPickers:UIPickerView = UIPickerView()

    override func viewDidLoad() {
        super.viewDidLoad()

        buildPickers = UIPickerView()
        buildPickers.delegate = self
        buildPickers.hidden = true;
        buildText.inputView = buildPickers
        buildText.text = buildings[0]        
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int{
        return 1
    }

    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int{
        println("Count: \(buildings.count)")
        return buildings.count
    }

    func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String! {
        println("creating title: \(buildings[row])")
        return buildings[row]
    }

    func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int)
    {
        println("Selected: \(buildings[row])")
        buildText.text = buildings[row]
        buildPickers.hidden = true;
    }

    func textFieldShouldBeginEditing(textField: UITextField) -> Bool {
        buildPickers.hidden = false
        return false
    }
}

The print statements are correct. For numberOfRows... and titleForRow it is printing the correct Strings.

But there is no prints for didSelectRow because, well, I can't select a row.

This is what I get:

You can ignore the Google Map in the background, that shouldn't interfere with the Picker View and is just set up in the StoryBoard.

The Grey window appears when I click on the textField but never shows any content. But the print statements say otherwise.

Does anyone know why this is the case?

via Chebli Mohamed