Allow deletion of primary email

On the Contact Summary tab, you can delete a contact's non-primary email, but you cannot delete their primary email. Seems like you should be able to delete any email, primary or not. If you delete a primary email, the next email on the list should become primary.

This is also kind of annoying if you want to add a new primary email and delete the old one, in which case you have to add the new email, make it primary, save, re-open the edit window and then delete the old primary email.