[racket] beware DrRacket and Dexpot interaction

In Windows 7:

Over the past four days I've been using DrRacket intensively.  During
this time it has crash on me at least twice a day, each time exiting
with error code 3 (according to the Puttycyg shell).

I eventually noticed that Dexpot (a virtual window manager for
Windows), which has otherwise been running fine, seemed to be
exhibiting some instability -- not immediately after the DrRacket
crashes, but also roughly 1-2 times a day.

So I turned off Dexpot entirely.  For 1.5 days since, DrRacket has not
crashed at all.

If you're using Dexpot, you may want to be wary of this.

For reference, I was running 1.5.9, Build 1503.  I have just upgraded
to the latest version/build and will start using the two together
again to see whether this continues.

[Of course, I can't rule out a hardware failure either.]

Shriram