What does inherit-compiler-output do?

I'm looking at differences b/w IDEA 6 and IDEA 7 and maven idea plugin generated iml files and I see that in the case where my stuff works there's inherit-compiler-output="true" for NewModuleRootManager

But why is it false for IDEA 7?

In IDEA 6 you wouldn't see the actual classes for the module that the web facet belongs to as a dependcy when building the war file. ... You would see the module dependency thru module settings but not when select what output you want copied to the war.

In IDEA 7 when you create a new module and then a web facet you do see the classes for the owning module as a dependency in both panels.