The invoicing product search function is not fit for purpose. You have to type the EXACT product name letter by letter to be able to find it. You should be able to type any part of the product name to populate the search list. For instance:
If I have a product called 'Black T-shirt with Skull Logo', I would like to be able type SKULL for the search result to return this product.
I may have 50 Items names 'Black T-shirt with xxxx Logo' and typing that out every time I want to add one is extremely inefficient, and frustrating to the point of unusable when you have thousands of products!
Products should be searchable by SKU as well.