How to make 'Recent Comments' the default tab
I'm sorry but I didn't follow you. What do you mean saying the Default Widget? If you want to use your theme widget you can use it separately. wpDiscuz Widgets addon also has a Recent Comments widget, you can use it in tabs of addon widgets. You can't put theme widgets in wpDiscuz Widgets addon Tabs. This is something impossible. The source of these data and HTML code are located in different places.
Ok, I see what do you mean. We'll take this under consideration.