[racket] Highlighting in DrRacket

>  The problem here is that the pink
> goes away while you're looking at it.   I can make some guesses as to why
> you might have made the pink highlighting time-out [...]

What version are you in?  There was a bug in 5.0.1 that caused the
pink highlight to disappear.  (Basically, when you have the buffer in
an unsaved state, DrRacket auto-saves.  Auto-saving changes the buffer
state, which causes the highlight to go away, just as editing does.)

Shriram