In V8 'new MouseEvent("click", {relatedTarget: window}).window' returns null. In JSC it returns window, which is a correct behavior. V8 should also return window.
Created attachment 185681 [details] Patch
Comment on attachment 185681 [details] Patch Interesting.
Comment on attachment 185681 [details] Patch Clearing flags on attachment: 185681 Committed r141383: <http://trac.webkit.org/changeset/141383>
All reviewed patches have been landed. Closing bug.