Hierarchy and overriding in extensions?

[VenomousFiligree]

I'm trying to override reference_basicclasses in the Foundation Core ruleset. I have included it in extension.xml and successfully added feat classes, however it would appear if I try and edit the likes of referenceinlineindex it defaults to the Foundation Core version?

[Ikael]

is referenceinlineindex used inside other windowclass? If that's the case you must make sure to include that windowclass in your extension as well.