Hi Hannes!

This morning I've just run into this exact same situation: putting a halt into a method, called by a morph's #drawOn:

makes the image unusable.

The problem stems from WorldState >> displayWorldSafely: being safe only for Errors and not for other kind of

Exceptions, and Halt being only an Exception not an Error.

For a quick fix add Halt to the handled exceptions in #displayWorldSafely:

[aWorld displayWorld. finished := true] on: Error, Halt do: [:ex |

Balázs