how to prevent storyboard from opening a window

Question

I am writing a simple application that loads into the status bar and when clicked it opens a popover under the status bar icon. I am using storyboards to define the UI I like to show in my popover. The thing is as soon as I instantiate the storyboard a window opens up. How can I prevent that? This is the code in my application delegate:

func applicationDidFinishLaunching(aNotification: NSNotification) {
    let mainBoard = NSStoryboard(name: "MainBoard", bundle: nil)
}

Answer 1

import Cocoa

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
    var defaultWindow:NSWindow!
    func applicationDidFinishLaunching(aNotification: NSNotification) {
        defaultWindow = NSApplication.sharedApplication().windows.first as? NSWindow
        defaultWindow.close()

    }
    func applicationWillTerminate(aNotification: NSNotification) {
        // Insert code here to tear down your application
    }
    @IBAction func menuClick(sender: AnyObject) {
        defaultWindow.makeKeyAndOrderFront(nil)
    }
}

update: Xcode 7.1.1 • Swift 2.1

NSApplication.sharedApplication().windows.first?.close()