[plt-scheme] Cleaner callback

Hi all,

Sometimes we just don't need any callback function, I usually
make them return null since they need to exist:
 (instantiate button% ()
      (label "Money comes and goes...")
      (parent statframe)
      (callback (lambda (button event) null)))

for example...

is there any cleaner way?

Best regards,

-- 
Paulo J. Matos : pocm(_at_)mega.ist.utl.pt
Instituto Superior Tecnico - Lisbon    
Software & Computer Engineering - A.I.
 - > http://mega.ist.utl.pt/~pocm 
 ---	
	Yes, God had a deadline...
		So, He wrote it all in Lisp!