Just noticed this in 3.2gamma:

Make a Rectangle.
Bring up a Viewer on the rectangle.

script1: rectangle's color _ red; when mouse down.
script2: rectangle's color _ blue; when mouse up.
Test it; works OK.

script3: rectangle's color _ green; when mouse still down.
Test it; works OK.

Now destroy script3.

The mouse-down script (script1) no longer works (though the mouse-up 
one does).

The event handler has had the mouseDown recipient and selector 
removed.

If I re-select "mouseDown" in script1, it works OK again.

-- 
Ned Konz
http://bike-nomad.com
GPG key ID: BEEA7EFE