Well, to be honest, I tried to turn that off, but the boundingboxes started to disappear again...
[Edit:]After trying again, I feel ashamed to admit it does work when the Density Shader isn't inverted. However, it's good you take a look at the files, because while I fixed the doubles I got with Object spacing of 2.4 by changing to 3, I still have some empty spots. How do I increase the coverage?
But it does work, so you may slap me in the face for frustrating you unneededly!
You made a great set of nodes we should all keep close by! [/Edit]