         
         configureCollectionView()
         adjustTrackingArea()
+        
+        NotificationCenter.default.addObserver(self, selector: #selector(self.windowDidChange), name: .NSWindowDidResize, object: nil)
+        
 
         let failureHandler: (Error) -> Void = { print($0.localizedDescription) }
 

        self.headerView?.frame.size.width = self.collectionView.frame.size.width
        self.headerView?.needsLayout = true
    }

    override func mouseEntered(with event: NSEvent) {
        var mouseOverItemIndex = NSNotFound

        }
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }
    
    @IBAction func newTweet(_ sender: Any) {
        let twitterService = NSSharingService(named: NSSharingServiceNamePostOnTwitter)
