Hey guys. I am having an issue with one of my projects. UICollectionViewCell in my UICollectionView has a plus button with the systemImage "plus". When clicked, its changing to systemImage "checkmark". The issue is, clicking one button, changes UI for every fifth cell. On top of that, animation does not finish. Alpha goes to 0, and then the image is being changed, alpha should go to 1 but never gets there. It stops somewhere between 0.7-0.8. Here is my animation block: private func animateButtonView(_ viewToAnimate: UIView) {         UIView.animate(withDuration: 0.2, animations: {viewToAnimate.alpha = 0}) { [weak self] (true) in             guard let self = self else { return }             switch true {             case true:                 DispatchQueue.main.async { self.addToFavoritesButton.setImage(SFSymbolsAsImg.checkmark, for: .normal) }                 UIView.animate(withDuration: 0.2, animations: {viewToAnimate.alpha = 1} )             case false:                 return             }         }     } Animation block is executed in my objective function that is called in addTarget for a button. I've asked that question on many forums and got not much. I'll appreciate any help. Many thanks!

I am testing iOS15 and some new functionalities of UIKit. I've encountered some issues, not sure how to solve them. I did not change that code. This is just a piece of code that worked perfectly with the iOS 14, now after updating my target, it throws an error. Xcode crashes the moment when my custom header for the UICollectionView of type UICollectionElementKindSectionHeader is being returned for the dataSource. Here is my code: private func configureDataSource() { dataSource = UICollectionViewDiffableDataSource<Section, Follower>(collectionView: collectionView, cellProvider: { (collectionView, indexPath, followers) -> UICollectionViewCell? in let cell = collectionView.dequeueReusableCell(withReuseIdentifier: FollowerCell.reuseId, for: indexPath) as! FollowerCell cell.set(on: followers) return cell }) dataSource.supplementaryViewProvider = { (collectionView, kind, indexPath) in let header = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: FollowersCollectionHeaderView.reuseId, for: indexPath) as! FollowersCollectionHeaderView header.set(with: self.user) return header } } The log says: the view returned from -collectionView:viewForSupplementaryElementOfKind:atIndexPath: does not match the element kind it is being used for. When asked for a view of element kind 'FollowersCollectionHeaderView' the data source dequeued a view registered for the element kind 'UICollectionElementKindSectionHeader'. I did cast UICollectionElementKindSectionHeader to FollowersCollectionHeaderView, therefore I am not sure what is the issue here. I've watched WWDC21 what's new in UIKit but haven't seen any mentioning of any change for that particular code. Any suggestions, what to fix in that code?