Search Customers in Invoice Screen & search for contact persons

Not a huge priority but when you're up to thousands of customers, it'd be good to be able to search for a customers name or business from the Invoice screen.

Also, on the search (currently under customers), shouldn't the default search also include the names of "contact persons". For example, if I have someone called Joe ring me up about an invoice, I have to go to "advanced search" and then "first name" to find which business name or organisation his invoice comes under as he's just listed as a "contact person"