CustomView Does not show up in StatusBar - macos

Question

I am trying to make a SystemStatusBar popover for Mac. (Roughly, translating this Cocoa app to a Swift app). However, the view that I am using never shows up and the popup appears in the bottom left of the screen replicating the StatusBarItem.
This is what I expect (and that happens in the example from case of example from the link):
and this is what actually shows up (in my, Swift version of the application) instead of the NSPopover being shown in the StatusBar [Showing or Hiding the popup is controlled by the two buttons as shown in the previous figure. In this screenshot I have not added that window as it remains the same.]:
This is the AppDelegate:
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
#IBOutlet weak var window: NSWindow!
var statusView : StatusView!
var popController: PopViewController!
#IBAction func showPop(sender: NSButton)
{
statusView.showPopup()
}
#IBAction func hidePop(sender: NSButton)
{
statusView.hidePopup()
}
func applicationDidFinishLaunching(aNotification: NSNotification)
{
var height = NSStatusBar.systemStatusBar().thickness
statusView = StatusView(frame: NSMakeRect(0, 0, CGFloat(height), CGFloat(height)))
}
}
The CustomView:
class StatusView : NSView, NSMenuDelegate
{
var imageView: NSImageView!
var statusItem: NSStatusItem!
var popover: NSPopover!
var popController: PopViewController!
required init? (coder: NSCoder)
{
super.init(coder: coder)
}
override init(frame frameRect: NSRect)
{
var height = NSStatusBar.systemStatusBar().thickness
imageView = NSImageView(frame: NSMakeRect(0, 0, CGFloat(height), CGFloat(height)))
statusItem = NSStatusBar.systemStatusBar().statusItemWithLength(CGFloat(height))
super.init(frame: frameRect)
imageView.image = NSImage(named: "mf-image-black.png")
self.addSubview(imageView)
statusItem.view = self
popover = NSPopover()
popController = PopViewController(nibName: "PopViewController", bundle: nil)
popController.view = self
popover.contentViewController = popController
}
func showPopup()
{
if(!popover.shown)
{
popover.showRelativeToRect(self.frame, ofView: self, preferredEdge: NSMinYEdge)
}
}
func hidePopup()
{
if(popover.shown)
{
popover.close()
}
}
}
and the ViewController:
class PopViewController: NSViewController
{
#IBOutlet var statusView: StatusView!
override init?(nibName: String?, bundle: NSBundle?) {
super.init(nibName: nibName, bundle: bundle)
}
required init?(coder: NSCoder)
{
super.init(coder: coder)
}
}
I am not exactly sure what is that I am missing here. The StatusItem never seems to make use of the PopViewController nib.