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.