[racket] perpetual "Online expansion running"

Aha.  No boxes were checked on the "View -> Check Syntax Mode" menu.  I 
don't know what Check Syntax was doing.

Neil Van Dyke wrote at 05/09/2012 07:11 PM:
> What does it mean if DrRacket's online Check Syntax indicator is blue, 
> and the tooltip says "Online expansion running", but CPU is 0%.
>
> I can run the code.  I can leave DrRacket idle for a long time, but 
> the indicator stays blue.  Disabling and then re-enabling online Check 
> Syntax doesn't help.  Quitting and restarting DrRacket doesn't help.
>
> A wild guess is that Check Syntax is secretly giving up, due to the 
> "require"s in this module (the size of the "require"-d stuff, or the 
> complexity of the "require" graph).  There's not much crazy syntax 
> transforming happening in the application code, if that matters.
>
> Neil V.