When composing an answer on a question that gets migrated you get a warning that the question is locked and after a reload you get redirected to the new site. However the answer box is empty.
AFAIK there is no way to recover the draft you started on the first site. This is fairly irritating.
use "migrated" instead of "locked" in the notification, this lets the user know that his efforts weren't entirely in vain.
when doing the redirect on reload also pass along the draft.