[racket] shift/release shift keys in universe module

Does releasing a shift key cause a key event in 2htdp/universe ?  I want to
distinguish between ordinary mouse click and shift click.  What I'd like is
to have a sequence like

keyevent:  "shift"  (or "rshift")
mouse-event: button-down [or whatever]
keyevent: ???    (I release the shift key)

I suppose I could experiment to find out, but it's quicker to ask :)

--Mitch
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.racket-lang.org/users/archive/attachments/20130314/85450a65/attachment.html>