Currently, developers are not able to change a WKScrollView's decelerationRate by explicitly setting it, e.g. webView.scrollView.decelerationRate = UIScrollViewDecelerationRateNormal; This fixes the deceleration rate to UIScrollViewDecelerationRateFast. This is because _preferredScrollDecelerationFactor in WKScrollView is not updated when [WKScrollView setDecelerationRate] is invoked, so when the snap points code determines whether the decelerationRate should be fast or whatever the preferred value is, the decelerationRate is always set to UIScrollViewDecelerationRateFast.
Created attachment 259173 [details]
Comment on attachment 259173 [details]
View in context: https://bugs.webkit.org/attachment.cgi?id=259173&action=review
> + https://bugs.webkit.org/show_bug.cgi?id=148086
There should be a radar url here too.
> + Updates the preferred scroll deceleration factor when the scrollView's decelerationRate is explicitly set.
Can you put more words here to say why this fixes the bug?
Committed r188541: <http://trac.webkit.org/changeset/188541>
(In reply to comment #4)
> Committed r188541: <http://trac.webkit.org/changeset/188541>
@Wenson: Can you specify what version of iOS this bug fix was released with? Still seems to be an issue in iOS 9.3 13E230.
As far as I know, this fix did not make it into iOS 9. Could you try it out on the iOS 10 beta?