My original post may have been confusing. I can add and delete attachments. No problem there. There used to be an option where you could select to "email with PO". That is gone. 

I like this function as I can attach my customers PO's to my Vendor PO (but do not email it with the PO) so I have it as a future reference.

That function is gone.

The function is still on the Invoices though.