Frank Shearar uploaded a new version of Tools to project The Trunk:
http://source.squeak.org/trunk/Tools-fbs.487.mcz

==================== Summary ====================

Name: Tools-fbs.487
Author: fbs
Time: 16 July 2013, 2:54:12.409 pm
UUID: 528e432c-a02e-e646-9a6e-3336c4e1c6a5
Ancestors: Tools-fbs.486

That missing colon makes the difference between a valid selector and a random symbol. (It could not possibly have worked!)

=============== Diff against Tools-fbs.486 ===============

Item was changed:
  ----- Method: Browser>>buildClassListSingletonWith: (in category 'toolbuilder') -----
  buildClassListSingletonWith: builder
  	| listSpec |
  	listSpec := builder pluggableListSpec new.
  	listSpec 
  		model: self;
  		list: #classListSingleton; 
  		getIndex: #indexIsOne; 
  		setIndex: #indexIsOne:; 
+ 		menu: #classListMenu:shifted:;
- 		menu: #classListMenu:shifted; 
  		keyPress: #classListKey:from:.
  	^listSpec
  !