Item and block entities stacking

In MC 1.3.2, item entities stack together when they're near each other. Where is the code for this behavior? Is this added by forge? Is there a way to disable it without editing base classes? Is there a config? Or is this just when i run it in eclipse.

I wanted to make a shower of the same item, but it just combines in midair and looks terrible. I wanted to make it so that my item doesn't stack like that while it is an entity.