WPF and theme-dependent style files
===

So I can create multiple XAML files in my Themes directory to make my user control Windows theme aware. All details are here: http://www.wpfmentor.com/2008/11/setting-up-your-applications-resource.html

I have changed my AssemblyInfo.cs accordingly:

    [assembly: ThemeInfo(
        ResourceDictionaryLocation.SourceAssembly,
        ResourceDictionaryLocation.SourceAssembly)]

But my problem is now that it doesn't work as I think it should and nobody really explains it. All is just so theoretical "put this file there and it works". But what do I have to write in those files exactly?!

I've tried it this way: All control styles with all setters and things go into Themes/Generic.xaml. Then I added Classic.xaml to make some adjustments for the classic theme which only includes some brushes for now. But when I run the app, my user control is just completely gone, it's invisible.

Then I tried to fumble around with MergedDictionaries but it didn't do anything. Only when I copy the entire contents of Generic.xaml into Classic.xaml, I can make the modifications I need and all works well.

So will I really have to copy my entire ResourceDictionary once for each theme I'm targeting? Can't I reuse 99% of it and only change the last bit that really is different? Should that work somehow, could somebody please finally explain to the world what needs to be done?