Created attachment 316865 [details] testcase Use "Find in page" in that text case to search "text" and highlight the single search match. Then scroll the overflow node: The highlighted text does not moved with the content of the overflow node. Extracting this from bug 163911, as that seems orthogonal.
Created attachment 335689 [details] testcase This is an extended testcase, showing that dynamic scrolls of the main frame or of the subframe make the selection disappear (contrary to desktop). So to summarize: - User scroll of a the main frame with hightlighted text works. - User scroll of a subframe with hightlighted text does not update the position of the highlighted text. - Programmatic scroll of the main frame or a subframe with hightlighted text makes the selection disappear.
Created attachment 373166 [details] Patch
Comment on attachment 373166 [details] Patch Clearing flags on attachment: 373166 Committed r246948: <https://trac.webkit.org/changeset/246948>
All reviewed patches have been landed. Closing bug.
<rdar://problem/52369021>