I'm currently designing a store management application to be used by employees of certain stores. At many points within the processes of this store, the user should be able to search the database of items that can be ordered from HQ, to collect them and then directly order them.
My current approach is to create a button in this application that is always visible, which slides the following modal window into view:
Never mind any usability flaws, sizing problems or missing functionality in this mockup - my question is about the general structure of this approach:
Do you know any Shopping Cart patterns that show a searchable order list in the same context as the shopping cart, i.e. the list of items I can order next to the list of items I actually have selected to order?
My developers have their reservations about this concept, since they don't know it. Their argument is that web shops typically don't show those two lists together. Sadly, my objection that a store application is not a web shop falls flat. My rationale for this concept is that the users know exactly what they need, and they want to complete this ordering thing as quick and painless as possible, in order to go on with their other work.
I feel that if I want to keep this approach, I need to provide examples or other rationales for my opinion though. So: does this approach make sense to you in the context I described? Can you point me to any examples of this approach?