https://www.w3.org/TR/css-display-3/#independent-formatting-context
<rdar://problem/58508015>
Created attachment 387451 [details] Patch
thanks Sam!
Comment on attachment 387451 [details] Patch Clearing flags on attachment: 387451 Committed r254410: <https://trac.webkit.org/changeset/254410>
All reviewed patches have been landed. Closing bug.