[racket] Frames within Frames?

At Mon, 16 Jul 2012 10:30:56 -0400, Justin Zamora wrote:
> How can I put frames inside of a master frame to implement multiple
> documents (e.g. http://images.appleinsider.com/win7task-090206-7.png)?

The old implementation of `racket/gui' supported MDI on Windows, but
since no one seemed to be using that feature, and since MDI seems to
have fallen out of favor generally, I didn't implement MDI support in
the new `racket/gui'.

If there's enough demand, it MDI support could be brought back.