It was Mutex. http://forum.world.st/How-to-resurrect-an-unrepsonsive-image-tp4168518p4178653.html

On Mon, Jan 2, 2012 at 3:28 PM, St�phane Ducasse <stephane.ducasse@inria.fr> wrote:
I remember reading somewhere that Monitor was broken in Pharo/Squeak?
I do not remember where.
Does anybody have experience with bad monitor behavior?
Because we got some bad experience with Monitor.

THe funny part is that now doing self inform: freezes to death our image.

Stef




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Mariano
http://marianopeck.wordpress.com