Production-Window? NOT-Production-Tab?

[dognose]

The Production-Window currently has 3 Tabs:

Items, Fluids, Buildings, each scaleable to some certain timeframes.

I'd love to have a 4th tab, showing each item that is NOT currently produced in some factory.

Basic purpose:
Review, what kind of items are not produced, so you know if you can request them through the logisitc network or not.

[Rseding91]

The main problem I see is: there are a *lot* of items that aren't in the recipe list that aren't produced in most games. Defining what should be shown in that GUI has no clear answer.