Could you explain why Tabs Widget doesnt actually look like Tabs

I've made a screenshot.

http://i.imgur.com/hya7ZuJ.png

This is not a "Tabs" Widget, where are the tabs?
Am I just going to have to download a Tabs plugin for a decent looking Tabs Menu?

I don't get this?

Also, it won't include certain other widgets, such as BBpress topics, comments, etc.

Hi!
Could you clarify the theme you are using? I installed the latest version of MyInterior theme and the Tab Widget works properly with this theme.
As for BBPress plugin, we don't support this plugin. And we can't guarantee the proper work of this plugin with the theme.

nothing shows on my theme either - Travel theme - where are the "tabs" supposed to show?

To use this widget you need to add Tabs widget to the sidebar and drag the necessary widgets to the Tabs widget area.