I have come across a problem with the Director documentation (there's a shocker
eh?) regarding Button component events that may be causing some confusion.

In the events section for the Button, it lists Button.click as the triggered
event. This is in fact incorrect and it is "onRelease" that gets triggered when
this button is pressed. Here is a sample snippet to help people on their way...

--Create the new object for the flash connection
myNewObject = newObject("Anything")

--Set the callBack for the sprite which has the button in it and specify the
Button event
--"onRelease" and the handler to be called in shockwave when the event is
triggered "#shockwaveHandler"
sprite(??).setCallBack(myNewObject, "onRelease" , #shockwaveHandler, me)

--Create the handler to handle that event
on shockwaveHandler me
--Put some code here to run when the Button is pressed
end

Although the documentation is atrocious, and your "workaround" might
work, it is unnecessary. If the member.eventPassMode = #passNever
(default) then you can attach a behavior to the sprite that implements
an "on click" handler and this will fire:
--
on click me
put "mouseUp"
end