In Reflector, an Addin is called a Package (IPackage interface). Each package can add multiple Windows (IWindow), which are the control appearing on the right, can add CommandBar items (ICommandBarItem, ICommandBarButton) to the context menus, and attach listeners to the event trigerred when the AssemblyBrowser changes of ActiveItem (IAssemblyBrowser.ActiveItemChanged). The … [Read more...] about Reflector Add-in Tutorial