[Pharo-dev] Did no find yet a way to reproduce QA concurrent access

[stepharo]

I thought that I could reproduce the QA concurrent access raising a DNU 
when we remove a method
but I failed.
I got again this bug.
What I did was selecting a method in Nautilus and removing this method 
after an implementors and from the message list browser.
But I cannot reproduce it.
Stef