I used to have a Word add-in that showed my open documents in tabs, similar to tabbed pages in a browser. But it's gone away somehow, so I'd like to reinstall a tabbing app or add-in.

Can anyone recommend such an add-in? It doesn't have to be free (I'm that desperate ;-)

See Office Tab by Extend Office.

Thanks for your recommendation, Charles. I'd looked at OfficeTab before, and liked its features. I've downloaded it now.