[Webkit-unassigned] [Bug 244097] New: "Wheel" events are not dispatched in iOS Safari when overscroll is disabled

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=244097

            Bug ID: 244097
           Summary: "Wheel" events are not dispatched in iOS Safari when
                    overscroll is disabled
           Product: WebKit
           Version: Safari 15
          Hardware: iPhone / iPad
                OS: iOS 15
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: Scrolling
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: jarod.gowgiel at gmail.com
                CC: inikolic at microsoft.com, simon.fraser at apple.com,
                    thorton at apple.com

In iOS Safari, scrolling with a connected mouse does not work on sites that have disabled overscroll with some specific CSS rules. Specifically, `wheel` events are not dispatched to elements that have `overflow: hidden` or `overflow: none` when a mouse wheel is used on them. As noted in the bug linked below, hiding the address bar seems to "fix" this problem (by re-enabling overscroll, I think).

Preconditions that are necessary for this bug to happen:
* A <meta> tag like: `<meta name="viewport" content="width=device-width, minimum-scale=1.0, maximum-scale=1.0, user-scalable=yes">`
* Specific `body` and `html` styling rules, with `width: 100%` and `height: 100%`

I've managed to generate a reproducible case at https://codepen.io/JarodG/pen/gOeZmpK?editors=1111. Note that, because of Codepen's handling of browser focus in the default editor, you'll need to follow a few setup steps if you don't have a "Pro" subscription:
* Fork the linked Codepen via the button in the bottom right toolbar.
* Open the forked Codepen in debug mode by replacing "pen" in the URL with "debug", or by using the "view" icon in the top right to switch to debug mode.

Notice: 
* Scrolling in any of the three boxes in debug mode in desktop Safari or Chrome causes `wheel` events to be properly dispatched.
* In a Simulator instance, or on an iPad, open the same debug view and connect a mouse (either via Bluetooth for a physical device, or via "Send Pointer to Device" in the simulator).
* Wheel events will only be dispatched to the first box, and not to either of the other boxes.

I believe this bug is related to https://bugs.webkit.org/show_bug.cgi?id=226080 - it may be the same issue, or it may not, since the link provided by inikolic at microsoft.com has since gone dark and I can't compare the structure of that page to my reproducible case.

thorton at apple.com, I'm adding you to the CC list here since you were mentioned in both the aforementioned bug, and https://bugs.webkit.org/show_bug.cgi?id=210071 which initially added `wheel` support for iOS.

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