Bug 240917

Created attachment 459763 [details] Code reproduction When scrolling on a container that has touch-action: manipulation the pointercancel event is not dispatched. However, when touch-action: pan-x pan-y pinch-zoom is set the pointercancel event is dispatched. Steps to reproduce: 1. Open attached code reproduction on Safari for iOS. 2. Open Developer Tools and inspect the page running in Safari. 3. Scroll on the scroll area with the header "touch-action: manipulation". Observe that the pointercancel event is not dispatched. 4. Scroll on the scroll area with the header "touch-action: pan-x pan-y pinch-zoom". Observe that the pointercancel event is dispatched. Expected Behavior: Since "manipulation" is an alias for "pan-x pan-y pinch-zoom" according to https://developer.mozilla.org/en-US/docs/Web/CSS/touch-action#values, I would expect the pointercancel event to be dispatched when touch-action is "manipulation". Actual Behavior: pointercancel is not dispatched when touch-action: manipulation. Other Info: - This issue does not reproduce in Chrome for Android. - I can reproduce this all the way back to iOS 13.0, so this behavior does not appear to have regressed.