I'm using the new per-detent backgroundEffect (iOS 26.1+) on UISheetPresentationControllerDetent. When the user drags the sheet between two detents with different effects, nothing changes during the drag; the previous detent's effect stays until the finger lifts, then a fixed-length cross-fade runs on its own, decoupled from the sheet's settle animation. It reads as a jump. Minimal setup (form sheet, nothing else): UISheetPresentationControllerDetent *medium = [UISheetPresentationControllerDetent mediumDetent]; UISheetPresentationControllerDetent *tall = [UISheetPresentationControllerDetent customDetentWithIdentifier:@"c90" resolver:^CGFloat(id<UISheetPresentationControllerDetentResolutionContext> ctx) { return ctx.maximumDetentValue * 0.9; }]; medium.backgroundEffect = nil; tall.backgroundEffect = [UIColorEffect effectWithColor:UIColor.systemBackgroundColor]; sheet.detents = @[ medium, tall ];Expected: the effect transition is driven by the drag progress between adjacent detents, or at least runs inside the same settle animation as the height change. Reproduces on iOS 26.5 (23F77) and 27.0 (24A434) Simulator with iPhone 17 Pro, iOS 27.1 (24A94401) Simulator with iPhone Duo. Xcode 27.1. Is this intended, and is there a supported way to tie the per-detent effect transition to the gesture? Filed as FB25459597.

I have already filed a bug report with a sample project via Feedback Assistant: FB22760723 When presenting a UIViewController using UIModalPresentationFormSheet alongside UISheetPresentationController with a small custom detent (e.g., around 300pt height), VoiceOver spatial swipe navigation breaks. The user is unable to swipe left or right to navigate sequentially through the accessible elements inside the sheet. Accessibility Inspector reveals that the focus seems to get trapped by the background layer (UIDimmingView / "dismiss popup"). If the sheet is taller (e.g., 600pt), the issue does not occur and swipe navigation works as expected Steps to Reproduce: Run the attached sample Objective-C/UIKit project. Turn on VoiceOver. Tap the “Open transparent modal” button to present the modal with UIModalPresentationOverFullScreen presentation. Tap the "Open form sheet" button to present the sheet (configured with a custom 300pt detent). Attempt to swipe right using VoiceOver to navigate to the next element (e.g., from the title label to the buttons). Expected Results: VoiceOver should smoothly navigate through the sequential accessibility elements inside the sheet's view hierarchy, respecting the bounds of the modal sheet. Actual Results: VoiceOver gets stuck. The swipe right/left gestures fail to move focus to the next element inside the sheet. Instead, focus often escapes to the background or doesn’t change completely.