Hi Stef. I notice that RPackage does not update the extension methods of removed classes. It is easy to reproduce in Pharo 2.0 by doing: (RPackageOrganizer default packageNamed: 'FreeType') allDefinedExtensionMethods (this fails because FreeType used to have a extension method in TTCFont which was removed) Or step by step: 1) Create package PackageX. 2) Create package PackageY and ClassY. 3) Create in ClassY a extension method with category *PackageX. If you now browse the instVar "classExtensionSelectors" of PackageX you will see ClassY. 4) Remove ClassY 5) notice that 'classExtensionSelectors' from PackageX still references ClassY. In fact, if you ask its extension methods you will have a KeyNotFound #ClassY in Smalltalk globals ;) So...I guess this is a bug. If true, I open an issue. Cheers, -- Mariano http://marianopeck.wordpress.com