The scrolling synchronization does not work, we do not have the call to synchronizeStateFromScrollingTree in Nicosia implementation.
Created attachment 426580 [details] WIP patch This patch fixes the problem, still checking some of the testing issues to confirm it.
Created attachment 426586 [details] Patch
Committed r276426 (236889@main): <https://commits.webkit.org/236889@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 426586 [details].