Sites with specific markup could encounter a problem where performing a horizontal scroll inside a div contained within a larger scrolling overflow could prevent subsequent vertical mouse wheel gestures from bubbling up to the enclosing div.
This was caused by the "scrolledToTop" or "scrolledToBottom" methods to improperly return false when the div was actually at the maximum scroll. I'm investigating why the result was sometimes incorrect (see Bug 131958) separately, but we can sidestep the issue by recognizing that scrollable areas that have a style encoded with "overflow-y = hidden" should always report that they are at the maximum scroll position.
Created attachment 229840 [details]
Comment on attachment 229840 [details]
Can this have a testcase?
Committed r167634: <http://trac.webkit.org/changeset/167634>
(In reply to comment #2)
> (From update of attachment 229840 [details])
> Can this have a testcase?
A new testcase will be added as part of Bug 131958.