Items swapped with disabled items quickly and then opening a chest the items are duped.
Note it must be more than one disabled item. They can be the same
I am now noticing that the disabled mace mining has a bit of lag to it. Also setting your hot bar using the disabled items in a new word does not make the new hot bar air and it saves the disabled items.
My test for the dupe were in creative sorry I believe though that in survival if you could get a way for the items to not get deleted then this would work the closest I got to replicating creative was by using the number keys to see the item for just a frame but the timing needed to do this and open a chest would be impossible.