Drop callbacks

Hello all, particularly Lispworks folks,

I'm playing with 5.1 (on OS X, 10.5), and I'm excited about the drag
and drop support. One question that came up very quickly as I was
playing with the example and some of mine own code.

The documentation for simple-pane reads:

drop-callback  should handle these values of stage:
:formats ...
:enter ...
:drag ...
:drop ...

I wrote up a pane with a drop callback that had

(ecase stage
  ((:formats) ...)
  ((:enter :drag) ...)
  ((:drop) ...))

and quickly got an error about having no matching case for :leave. So
I'd misread the phrase "should handle these values of stage" as being
an exhaustive list, when it's not (which is OK). I just want to check
that I'm not supposed to be doing anything for the :leave stage (or
any other stages that I haven't yet run into).

Thanks!

-- 
=====================
Joshua Taylor
tayloj@cs.rpi.edu, jtaylor@alum.rpi.edu

"A lot of good things went down one time,
 back in the goodle days."
 John Hartford