Web pages are not responding correctly to changes in the "Reduce motion" accessibility setting under System Preferences > Accessibility > Display. This can for example be seen on https://webkit.org/blog-files/prefers-reduced-motion/prm.htm, while changing the setting.
Created attachment 406875 [details] Patch
Created attachment 406880 [details] Patch
<rdar://problem/66343795>
Comment on attachment 406880 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=406880&action=review > Source/WebKit/ChangeLog:3 > + [macOS] Web pages are not responding correctly to changes in "Reduce motion" setting How did we happen to overlook this one but not others? Are there any more of these?
(In reply to Darin Adler from comment #4) > Comment on attachment 406880 [details] > Patch > > View in context: > https://bugs.webkit.org/attachment.cgi?id=406880&action=review > > > Source/WebKit/ChangeLog:3 > > + [macOS] Web pages are not responding correctly to changes in "Reduce motion" setting > > How did we happen to overlook this one but not others? Are there any more of > these? Yes, there are potentially more of these cases, since this race is a general issue when updating preferences from the UI process, where the race is usually won by the notification. It might be possible to solve this in a more general way, but I have not been able to think of a way to do that so far. I will try to think of a more general solution. Thanks for reviewing!
Created attachment 406930 [details] Patch
Created attachment 406931 [details] Patch
Created attachment 406935 [details] Patch
The new API test is succeeding locally, but failing on the bots.
Created attachment 406937 [details] Patch
Created attachment 406953 [details] Patch
Created attachment 406955 [details] Patch
Created attachment 406975 [details] Patch
Created attachment 406978 [details] Patch
Created attachment 406981 [details] Patch
Created attachment 406988 [details] Patch
Created attachment 406995 [details] Patch
Created attachment 406997 [details] Patch
Committed r265996: <https://trac.webkit.org/changeset/265996> All reviewed patches have been landed. Closing bug and clearing flags on attachment 406997 [details].
How many other preferences are going to suffer from this same bug?
I asked the same question and the answer is in comment #5.