Some items have only 1 per slot, but others have more. The most common case is 10 - one item slot can hold 10 of that item.
So, even if you already have items reaching your inventory capacity cap, your inventory is still not full. For example, one of your item slot have 3 Dry Spell, which can hold 10 in this item slot, so you can still fill 7 Dry Spells into your inventory.
If you take 7 more Dry Spells from storage, there is no problem.
However, you cannot buy any Dry Spell - the quantity can go up to 7 (without increasing "Inventory Slots Used" value), but the "Checkout" button is never available.
So, even if you already have items reaching your inventory capacity cap, your inventory is still not full. For example, one of your item slot have 3 Dry Spell, which can hold 10 in this item slot, so you can still fill 7 Dry Spells into your inventory.
If you take 7 more Dry Spells from storage, there is no problem.
However, you cannot buy any Dry Spell - the quantity can go up to 7 (without increasing "Inventory Slots Used" value), but the "Checkout" button is never available.
