One note about Scratch... I think an older version of Squeak is being  
used- something in the 2.x world of things. I know this because, for  
some reason, 2.x images don't work quite right on my OS X VM  
(3.8.12beta4U). The mouse events are transposed 20 pixels below where  
my actual pointer is in all my 2.x images... and so in Scratch as  well.

Not that this first-class sleuthing, but it struck me as interesting  
that they were using a 2.x version of Squeak for Scratch.

Regards,
Aaron