WAPharoWalkback misuses debugger API

[GoogleCodeExporter]

WAPharoWalkback expects the following code to work:

Semaphore forMutualExclusion critical: [
    | sender |
    sender := thisContext sender.
    sender tempAt: sender tempScopedNames size ]

However this does not work with a Closure VM see:
http://lists.gforge.inria.fr/pipermail/pharo-project/2011-September/053729.html

Original issue reported on code.google.com by philippe...@gmail.com on 13 Sep 2011 at 8:02