Hello, I'm running pharo 4 and I'm having a problem. I recently renamed a class using the rename: menu item in the standard system browser (I believe it's called Nautilus) and now I am getting uncaught exceptions whenever I add or remove a method (three debugger windows pop up). Here is the stack trace; any advice? Thank you. Lyn Author: LynHeadley Date: 2015-10-13T08:51:16.837987-07:00 UndefinedObject(Object)>>doesNotUnderstand: #theMetaClass RGMetaclassDefinition>>realClass RGMethodDefinition(RGElementDefinition)>>realParent RGMethodDefinition(RGElementDefinition)>>realClass RGMethodDefinition>>methodClass ByteSymbol(Symbol)>>value: OrderedCollection>>collect: MessageBrowser>>buildHierarchyForMessages: MessageBrowser>>cacheHierarchyForClasses: MessageBrowser>>messages: [ (item methodClass notNil and: [ item methodClass isObsolete not ]) ifTrue: [ | sel text boolean | boolean := textModel hasUnacceptedEdits. boolean ifTrue: [ text := textModel pendingText ]. sel := listModel selectedItem. self messages: (listModel listItems add: item asFullRingDefinition; yourself). listModel setSelectedItem: sel. boolean ifTrue: [ textModel pendingText: text ] ] ] in MessageBrowser>>methodAdded: WorldState>>runStepMethodsIn: WorldMorph>>runStepMethods WorldState>>doOneCycleNowFor: WorldState>>doOneCycleFor: WorldMorph>>doOneCycle [ [ World doOneCycle. Processor yield. false ] whileFalse: [ ] ] in MorphicUIManager>>spawnNewProcess [ self value. Processor terminateActive ] in BlockClosure>>newProcess