While looking at the Magritte exercices proposed by Lukas at
http://www.lukas-renggli.ch/ I founded myself locked with the exercice-18.

I found the solution might be:

MAPersonModel>>description
	^super description copy;
		add: CustomDescription ;
		yourself

But it appears to lock the image, when updating from the web browser

Then if I execute a few 'MAPersonModel new description', I got a growing
   description (insepcting 'MAPersonModel description'), which may
explain the locked image. However I don't understand what make the
description growing.

Hilaire