I'm not completly sure how it works but.. sometimes it happened, sometimes it won't happen, but after a several tries it happens.

1. Place several tiles of a material
2. Drag a box over these tiles (perhaps to a full block)
3. Break the tile with a pickaxe
   (4. Repeat)
4. After a while it will drop tiles and your inventory fills endlessly with tiles, which you can put into your bag and drag out to full blocks (until the tiles despawn)

By the way, you get the full tiles into your bag as well.

I've reported on it too. But with more info of what I did. Found yet another exploit that I reported, so we just have to wait for an updated version

Should be fixed in the newest pre release 127, if it still persists just reopen this issue.