[racket] Debug button unavailable when is should not be

Hello,

I once implemented a DSL called "slon" in Racket.
My programs start with "#lang slon", and I open
them in DrRacket, edit, run, and debug them.

To make Racket aware of the DSL, I can either put a symbolic
link to my code into the standard collects directory:

ln -s /home/dpavlov/work/slon ~/.racket/5.2.1/collects

or alternatively I can use DrRacket's GUI to add the "work"
folder itself into collection paths: Choose Language ->
Details -> Collection Paths -> Add -> /home/dpavlov/work.

The problem is: the "Check Syntax", "Debug", and "Macro Stepper"
buttons are absent on my ".slon" programs when I use the second
approach. The "Run" and "Stop" buttons are there (and work) in
both cases, but the "Check Syntax", "Debug", and "Macro Stepper"
are there only if I put the symbolic link to ~/.racket/5.2.1/collects.

Any comments?


Best regards,

Dmitry