If you undo an edit command, you cannot redo it. This is because WebEditCommandProxy::unapply() and WebEditCommandProxy::reapply() are registering the wrong edit command when an undo or redo happens. For example, when we unapply(), we should register a Redo command, not an Undo command.
Created attachment 85103 [details]
Committed r80603: <http://trac.webkit.org/changeset/80603>