On Creative, getting an item into hotbar should not delete an existing item

When we press any number on the numpad while in creative inventory, we will get a full stack of item or block we selected into the slot we chose on the numpad.

However, it removes the item that was previously in that slot, which is really annoying.

In that case, the item we had in that slot should simply be moved into another slot, it should get deleted only if the inventory is completely full.