In the invoice module you can only really search for a specific invoice by invoice number - that's great if you have the invoice number to hand or can remember it, but wouldn't it be great if you could search for invoices by customer (I know you can go into the customer module and search that way but that's less direct, and surely todays software should by default be intuitive and direct?)
It woud be extremely helpful if the customer order number was shown on the invoice and stats page