ScrollEdgeEffectBlurIssue

Minimal iOS repro project for scroll edge effect and blur behavior across UIKit and SwiftUI.

This repo exists so other developers can inspect, reproduce, and help debug scroll edge effect behavior around edge-attached controls, blur, and safeAreaBar.

The screenshots and current repro notes are captured against an iOS 27.0 simulator, where the issues are easier to see.

The sample compares these cases:

• UITableView in a UINavigationController
• UICollectionView in a custom UIViewController
• UICollectionViewController
• SwiftUI List
• SwiftUI ScrollView with LazyVStack

Each screen exposes the scroll edge effect style controls for automatic, hard, and soft, plus top and bottom edge-attached controls. The SwiftUI list sample includes an inline note around the safeAreaBar(edge: .top) placement that appears related to janky scrolling.

Suspected Bugs

These are the behaviors this project is trying to make obvious:

• Top edge blur can obscure or wash out the first visible row behind the floating effect-style control.
• Bottom edge blur can create an oversized hazy band around the floating action button and tab bar.
• SwiftUI List appears sensitive to where safeAreaBar(edge: .top) is attached; placing it inside the NavigationStack can make scrolling feel janky.
• On iOS 27.0, UI settling after tab changes and menu presentation appears noticeably less stable while capturing snapshots.
• The same edge-control pattern does not look identical across UIKit UITableView, UIKit UICollectionView, UICollectionViewController, SwiftUI List, and SwiftUI ScrollView.

Screenshots

Captured on iOS 27.0 using an iPhone 17 Pro simulator.

UIKit Table	UIKit Grid	UICollectionViewController
SwiftUI List	SwiftUI ScrollView	Effect Style Menu

Repro Notes

• The top control changes between .automatic, .hard, and .soft.
• The floating bottom button is attached to the bottom scroll edge.
• In SwiftUIListSampleView, moving the top safeAreaBar(edge: .top) inside the NavigationStack reproduces the janky scroll behavior this project is meant to isolate.
• UIKit samples use UIScrollEdgeElementContainerInteraction; SwiftUI samples use safeAreaBar and scrollEdgeEffectStyle.
• Prefer testing on iOS 27.0 first; the blur and scroll-edge artifacts are more visible than on iOS 26.5.

Project Layout

ScrollEdgeEffectBlurIssue/
  App/                    App lifecycle and root tab/sidebar controller
  Shared/
    Models/               Cross-framework edge effect style model
    Data/                 Small sample data helpers
  Samples/
    UIKit/
      ViewControllers/    UITableView, UICollectionView, and UICollectionViewController samples
      Views/              Reusable UIKit cells/views
      Support/            UIKit scroll edge effect wiring
    SwiftUI/
      Views/              List and ScrollView repro screens
      Controls/           Top menu and bottom button used by SwiftUI samples
  Assets.xcassets/

Requirements

• Xcode 26.5 or newer
• iOS 27.0 simulator/runtime recommended for debugging the visible artifacts
• iOS 26.0 or newer deployment target

Run

Open ScrollEdgeEffectBlurIssue.xcodeproj, select the ScrollEdgeEffectBlurIssue scheme, and run on an iPhone or iPad simulator.

From the command line:

xcodebuild \
  -project ScrollEdgeEffectBlurIssue.xcodeproj \
  -scheme ScrollEdgeEffectBlurIssue \
  -destination 'platform=iOS Simulator,name=iPhone 17 Pro,OS=27.0' \
  build

What To Look At

• App entry point and tabs: ScrollEdgeEffectBlurIssue/App/RootTabBarController.swift
• Shared edge effect model: ScrollEdgeEffectBlurIssue/Shared/Models/EdgeEffectChoice.swift
• UIKit scroll edge effect setup: ScrollEdgeEffectBlurIssue/Samples/UIKit/Support/UIKitEdgeEffectController.swift
• SwiftUI List behavior: ScrollEdgeEffectBlurIssue/Samples/SwiftUI/Views/SwiftUIListSampleView.swift
• SwiftUI ScrollView behavior: ScrollEdgeEffectBlurIssue/Samples/SwiftUI/Views/SwiftUIScrollSampleView.swift