See bug 1547409. Moving webcompat whiteboard tags to project flags.

Ksenia, can you take a look at this please?

In this file:

The following event listener is added to a div with the graph:

this.$ = s_s(this.Ya, s_k.eh ? "DOMMouseScroll" : "mousewheel", this, b),

where s_k.eh is a check for a User Agent, so DOMMouseScroll is added in Firefox and mousewheel in Chrome.

When the event is firing there is a call to preventDefault in this file:

  s_Gd.prototype.preventDefault = function () {
    s_Gd.Ua.preventDefault.call(this);
    var a = this.zd;
    if (a.preventDefault) a.preventDefault();
     else if (a.returnValue = !1, s_wda) try {
      if (a.ctrlKey || 112 <= a.keyCode && 123 >= a.keyCode) a.keyCode = - 1
    } catch (b) {
    }

While preventDefault works for mousewheel, it doesn't work for DOMMouseScroll (need to call preventDefault() of wheel events). So the page scrolls up and down because of that.

I think both of those legacy events listeners can be replaced by wheel, though it will require some changes in the event handler code.

Here is a related bug https://bugzilla.mozilla.org/show_bug.cgi?id=1529953 about mousewheel support

ni? myself to reach out to Google here.

I sent an email to our partner list.

No response so far, reaching out to our Google search mailing list.

Updating flags based on duplicate Bug 1699400

Managed to reproduce the issue also on Ubuntu 20 X64. with build 96.0b2-snap.
In comparison with the Windows repro steps, on ubuntu the touchpad scroll must be longer in order for the page to scroll.

Also reproducible on Beta v105.0b8 on Windows 7.