[racket-dev] Fix bug in DrRacket's language configuration dialog

Hi,

I've just created the pull request 186 (https://github.com/plt/racket/pull/186) which fixes a bug with the language configuration dialog.
As I have disabled a bunch of languages for which I have no use, the language configuration dialog is not showing anymore.

My patch only fixes the issue but I think it could be taken a step further.
In my case, the "Teaching Languages" category becomes empty (see http://pmechai.free.fr/langcfgdialog.png) so I think it should not be displayed anymore or at least be disabled.
If it makes sense to you I would be happy to make a patch for this.


Regards,
Philippe Mechaï