When you drag an item over another item, either in your bag or cabinet, it should simply swap places.
If i have a packed bag and cabinet and i want to swap items form bag to cabinet, i need to drop an item, move an item over from the cabinet, then move the item from my bag to the cabinet.
It seems much simpler if dragging an item over another would swap it, or open a context menu with options and one of them could be swap?