         self.headerView?.frame.size.width = self.collectionView.frame.size.width
         self.headerView?.needsLayout = true
     }
+    
+    func windowDidChange() {
+        let tweetArray: [Tweet] = self.tweets.map {
+            $0.itemHeight = 0
+            return $0
+        }
+        
+        self.tweets = tweetArray
+    }
 
     override func mouseEntered(with event: NSEvent) {
         var mouseOverItemIndex = NSNotFound

            
            let glyphRange = layoutManager.glyphRange(for: textContainer)
            var bounds = layoutManager.boundingRect(forGlyphRange: glyphRange, in: textContainer)
            bounds.size.height += 28
            bounds.size.width = collectionView.bounds.width
            
            tweet.itemHeight = bounds.height

        }
    }

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