Disappear the text and press the cell

I have been using the UICollectionviewController. So , we try to make a transition to another screen by pressing the cell . But , the text that has been put in a cell will want to disappear when you press the cell . Could you tell me the reason for this ?


・ViewController

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell:CustomCell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! CustomCell
        cell.category.text = " BBBBBB ";
        cell.category.backgroundColor = UIColor.blueColor();
        cell.date.text = "2016-03-26";
        cell.title.text = "AAAAAAAAAAAA";
        cell.imgSample.image = UIImage(named: "CCCCC.png")
        cell.backgroundColor = UIColor.whiteColor()
        /
        cell.layer.masksToBounds = false;
        cell.layer.shadowOffset = CGSizeMake(0.0, 0.3);
        cell.layer.shadowOpacity = 0.2;
        cell.layer.shadowRadius = 0.5;
        return cell
    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
        let width: CGFloat = self.view.frame.width / 2 - 17.5
            let height: CGFloat = 220
            return CGSize(width: width, height: height)
    }

    func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
        return 1
    }

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 50;
    }
Disappear the text and press the cell
 
 
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