This part was missing when the tear-off objects were removed. Any change in the standard properties of these elements through DOM will fail because SVGElement:: commitPropertyChange() will not be able to find the attribute name of the SVGProperty.
Created attachment 368295 [details] Patch
<rdar://problem/50113907>
Comment on attachment 368295 [details] Patch Clearing flags on attachment: 368295 Committed r244690: <https://trac.webkit.org/changeset/244690>
All reviewed patches have been landed. Closing bug.