Currently when printing invoices you can elect to email as well, if you set the printer to be intereactive.  I personally think the email should be marked as printed if you email it.  Currently they stack up after a time, and you end up with a print screen like the image to the left. 

Is it possible that clicking mail (after checking it got sent) will make the invoice or document as printed.

It also would be helpful if the invoice description held some valid data.

Ben C