The native button will show additional object (class) specific methods (or properties) that are not part of the 'standard' set of methods or properties that a particular object class has. They can sometimes allow you to do extra things with an object besides the common methods such as custom developer created methods for an object. You can access them using the addtional object:

Window(''Test Window'').WinList(''TestList'').Object.ClearAll

Use this as a general rule. You might need to research the particular object online or talk to a developer about a native method or property to understand how it works.