Inventory button

I think we all need an option to check our inventories. The "Sell" button was removed and now it would be good for us to have "Inventory" button where we can check all upgrading items we have. We are buying tons of materials from the Shipments every day and they are stored ... somewhere. I know, you can click on some material to see how many of them you have stored, but still it would be good to have access to inventory.
I'm low lvl at this moment, but i'm buying purple shipments also, which i'm gonna start using after a week or so. Right now i can't see where they are.