Basically inert InsertionPoint has no meaning. We don't need to cast it to InsertionPoint. So it would be good to have isActiveInsertionPoint instead of isInsertionPoint so that we don't miss isActive check.
Created attachment 171156 [details] Patch
Comment on attachment 171156 [details] Patch Clearing flags on attachment: 171156 Committed r132791: <http://trac.webkit.org/changeset/132791>
All reviewed patches have been landed. Closing bug.