Instead of showing just the number of an item in inventory, show it and the maximum number, like you do with the bags and toolboxes. It minimizes the number of clicks required to check how many more I can gather or make to fill the slot.
And, for me and many people with RSI, carpal tunnel, or just plain "bad hands", each click hurts.
EXAMPLE: Instead of "Flour 31", show "Flour 31/80"