Hi ! In discovery for why screen gestures were not being deferred when using correct function in an Objective-C/C++ UIViewController discovered this issue Does not affect Swift Tools Tested: Xcode 13/14 Beta iOS Target 12 + Deferring gestures when using Objective-C UIViewController does not work using the normal bitwise op or the default Apple created bitwise op pipes ( | ) UIRectEdgeAll - Does not work: - (UIRectEdge)preferredScreenEdgesDeferringSystemGestures {     return UIRectEdgeAll; } UIRectEdge - using | - Does not work: - (UIRectEdge)preferredScreenEdgesDeferringSystemGestures {     UIRectEdge edges = UIRectEdgeNone; edges | UIRectEdgeTop;       edges | UIRectEdgeBottom;       edges | UIRectEdgeLeft;       edges | UIRectEdgeRight;     return edges; } Working solution for Objective-C use in UIViewController to use |= instead of | - (UIRectEdge)preferredScreenEdgesDeferringSystemGestures {     UIRectEdge edges = UIRectEdgeNone; edges |= UIRectEdgeTop;       edges |= UIRectEdgeBottom;       edges |= UIRectEdgeLeft;       edges |= UIRectEdgeRight;     return edges; } Issue originates in Objective-C code here for UIRectEdgeAll : UIKit/UIGeometry.h typedef NS_OPTIONS(NSUInteger, UIRectEdge) {     UIRectEdgeNone   = 0,     UIRectEdgeTop    = 1 << 0,     UIRectEdgeLeft   = 1 << 1,     UIRectEdgeBottom = 1 << 2,     UIRectEdgeRight  = 1 << 3,     UIRectEdgeAll    = UIRectEdgeTop | UIRectEdgeLeft | UIRectEdgeBottom | UIRectEdgeRight } API_AVAILABLE(ios(7.0)); Pipes used does not work: (use of |) UIRectEdgeAll    = UIRectEdgeTop | UIRectEdgeLeft | UIRectEdgeBottom | UIRectEdgeRight Solution (for Apple Engineers) : Change bitwise pipe to instead of | to be |= (or equal to, += basically) in UIKit/UIGeometry.h