Dealing with empty groups...

[Richard Gaskin]

Lynch, Jonathan wrote:
> Even though I have a couple workable solutions to the problem at hand, I
> am interested in understanding the underlying issue, because I can see
> other uses for empty and/or nested groups in the future.

Groups are containers for controls, but are not controls themselves. 
The messages you see passed to the group are generated by events on the 
controls. AFAIK both empty and non-empty groups do not respond to user 
events (mouseDown, mouseUp, etc.), only their controls do.  As a 
container for controls, the group can have a script to handle messages 
triggered by events on controls, but will not respond to those events 
themselves.

This is verifiable with this simple experiment:  make a new stack, but a 
button in it, group it, size the group so that it's much larger than the 
button, then lock its location so it stays that way.  Put this in the 
group's script:

on mouseUp
   put the milliseconds
end mouseUp

Then switch to the browse tool:  When you click on the button you get 
the milliseconds in the Message Box, but clicking in the empty areas of 
  the group does nothing.

--
  Richard Gaskin
  Fourth World Media Corporation
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