Let's fix this properly. - ALLOW swaps that take an item in a stack-limited container and try to swap it with another item that's stacked more than the container allows. - TRY to take just one from that stack and leave the rest in the old inventory, while also depositing the item that was dragged out. - CANCEL the process if the player has no inventory space for the new item (since unlike a normal drag-swap, we need an extra slot for the split item).