A new version of System was added to project The Inbox:
http://source.squeak.org/inbox/System-fbs.427.mcz

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

Name: System-fbs.427
Author: fbs
Time: 31 March 2011, 5:27:22.312 pm
UUID: df509a59-83f4-eb43-8f07-bdc931fb9c1b
Ancestors: System-ul.426

Returning the instantiated Browser greatly aids testing.

=============== Diff against System-ul.426 ===============

Item was changed:
  ----- Method: SystemNavigation>>spawnHierarchyForClass:selector: (in category 'browse') -----
  spawnHierarchyForClass: aClass selector: aSelector
  	"Create and schedule a new class hierarchy browser on the requested class/selector."
  	"SystemNavigation default spawnHierarchyForClass: SmallInteger selector: #hash"
  
  	(aClass == nil)  ifTrue: [^ self].
+ 	^ ToolSet browseHierarchy: aClass selector: aSelector
- 	ToolSet browseHierarchy: aClass selector: aSelector
  !