Looking at the code, I see that no config file is in use, and looking deeper into it I see that the shift+right click extract behaviour is hard coded (See here). While some people might get used to this, the ones of use who use jabba barrels will acknowledge that their default is shift=stack. While Storage Drawers uses the opposite, there is a config option to invert it.
This is a feature request, requesting the implementation of a config file and the option to invert shift+click behaviour.