I looked at your code and you placed self error: there too (basically
#validateChild:titled:in:). But if I do this, I break my kernel. So how
should I do this?
Strang, I've never seen this and I'm unable to reproduce.
The error and validation handling in Magritte is certainly a dark part
of the framework, it is trying to collect all errors by resuming
certain exceptions and therefor jumps around in the code. However this
doesn't work quite well as I expect, it definitely needs a different
concept and some more work.
Try to load the latest packages, I added an exception hander around the
command validation so that any error is transformed into a Magritte
error. Does this help?