1.3 crash and burn

Hi,

I'm starting to think 1.3 isn't quite ready for prime time.

http://picpaste.com/Pharo_1_3_crash-oRMNkNb8.png

I had selected asBTreeItem and pressed the delete key.

I've kept a complete copy of this 1.3 install directory if anyone wants
to dig into this crash. I'm pretty sure this was from the single click
distribution.

Jonathan.