In order to prevent me from accidentally editing invoices I’ve already sent to a client, I’d like Cakedesk to lock invoices after I have exported them. Locked invoices should be read-only (i.e. you shouldn’t be able to edit details such as the recipient, the line items, invoice text, my company details, or even the template). I’d basically like the invoice to be preserved exactly as it was when I exported it. It’s sometimes necessary to update an invoice after it has been exported, for example to fix an error before the invoices was sent to a client. This should still be possible, but it should require explicit confirmation to "unlock" the invoice.
