When using UICollectionViewCompositionalLayout and creating a layout that supports pinned supplementary items and additionally having a section that has orthogonalScrollingBehavior the pinned header will disappear as soon as you scroll over the section with the orthogonalScrollingBehavior. A simple layout that demonstrates how it breaks looks like this
This is an adapted part of the code provided by this example: https://developer.apple.com/documentation/uikit/views_and_controls/collection_views/implementing_modern_collection_views
Code Block func createLayout() -> UICollectionViewLayout { let itemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .fractionalHeight(1.0)) let item = NSCollectionLayoutItem(layoutSize: itemSize) let groupSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .absolute(44)) let group = NSCollectionLayoutGroup.horizontal(layoutSize: groupSize, subitems: [item]) let section = NSCollectionLayoutSection(group: group) section.interGroupSpacing = 5 section.orthogonalScrollingBehavior = .continuous section.contentInsets = NSDirectionalEdgeInsets(top: 0, leading: 10, bottom: 0, trailing: 10) let sectionHeader = NSCollectionLayoutBoundarySupplementaryItem( layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .estimated(44)), elementKind: PinnedSectionHeaderFooterViewController.sectionHeaderElementKind, alignment: .top) let sectionFooter = NSCollectionLayoutBoundarySupplementaryItem( layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .estimated(44)), elementKind: PinnedSectionHeaderFooterViewController.sectionFooterElementKind, alignment: .bottom) sectionHeader.pinToVisibleBounds = true sectionHeader.zIndex = 2 section.boundarySupplementaryItems = [sectionHeader, sectionFooter] let layout = UICollectionViewCompositionalLayout(section: section) let layoutHeaderHeader = NSCollectionLayoutBoundarySupplementaryItem( layoutSize: NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .estimated(44)), elementKind: PinnedSectionHeaderFooterViewController.layoutHeaderElementKind, alignment: .top) let configuration = UICollectionViewCompositionalLayoutConfiguration() layoutHeaderHeader.pinToVisibleBounds = true configuration.boundarySupplementaryItems = [layoutHeaderHeader] layout.configuration = configuration return layout }
This is an adapted part of the code provided by this example: https://developer.apple.com/documentation/uikit/views_and_controls/collection_views/implementing_modern_collection_views
