Some time ago a new class of variable binding was introduced
(ReadOnlyVariableBinding, a subclass of LookupKey) so that global class
names could be 'protected' in the Smalltalk global dictionary. The
classes around at that time appear to have been converted to use of it.
However, a load of new classes still have plain old Associations and are
thus not protected in this manner. I guess the compiler related code
wasn't altered; another unfinished job.

Try
Smalltalk associations select:[:assn | assn class ~= ReadOnlyVariableBinding]
to see a list of the classes not protected. I find 671 in a 3.8-6527
image I've done a bit of fiddling in, along with 1128 that are
protected.

tim
--
Tim Rowledge, tim at sumeru.stanford.edu, http://sumeru.stanford.edu/tim
Useful random insult:- Result of a first cousin marriage.