Note, this error is very hard to reproduce. It happened only few times when i typing in an OB code pane and method source is considerably big. I suspect that this bug is triggered because i'm using a new scheduler, and uncovers a concurrency issue in SHParserST80>>styleInBackgroundProcess:. ---------------- Error: attempt to index non-existent element in an ordered collection 2 May 2009 1:39:33 pm VM: Win32 - a SmalltalkImage Image: Pharo0.1 [Latest update: #10292] SecurityManager state: Restricted: false FileAccess: true SocketAccess: true Working Dir F:\projects\pharo-freetype\Squeak-new-scheduling Trusted Dir F:\projects\pharo-freetype\Squeak-new-scheduling\sig Untrusted Dir G:\usr\sig\docs\My Squeak OrderedCollection(Object)>>error: Receiver: an OrderedCollection(a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange...etc... Arguments and temporary variables: aString: 'attempt to index non-existent element in an ordered collection' Receiver's instance variables: array: an Array(a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange a S...etc... firstIndex: 66 lastIndex: 77 OrderedCollection>>errorNoSuchElement Receiver: an OrderedCollection(a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange...etc... Arguments and temporary variables: Receiver's instance variables: array: an Array(a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange a S...etc... firstIndex: 66 lastIndex: 77 OrderedCollection>>at: Receiver: an OrderedCollection(a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange...etc... Arguments and temporary variables: anInteger: 130 Receiver's instance variables: array: an Array(a SHRange a SHRange a SHRange a SHRange a SHRange a SHRange a S...etc... firstIndex: 66 lastIndex: 77 [] in [] in SHParserST80>>parseKeyword Receiver: a SHParserST80 Arguments and temporary variables: <<error during printing> Receiver's instance variables: classOrMetaClass: AdvancedDelay source: 'performCommonChecksAt: nowTick "Perform various checks, each time we...etc... workspace: nil arguments: a Dictionary(0->an OrderedCollection('nowTick') ) sourcePosition: 452 currentToken: 'ScheduledDelay' currentTokenFirst: $S temporaries: a Dictionary(0->an OrderedCollection('nowTick' 'nextTick') ) instanceVariables: #('delayDuration' 'resumptionTime' 'waitingProcess' 'beingWa...etc... errorBlock: [closure] in SHParserST80>>parse: currentTokenSourcePosition: 438 blockDepth: 0 bracketDepth: 0 ranges: an OrderedCollection(a SHRange a SHRange a SHRange a SHRange a SHRange ...etc... environment: Smalltalk --- The full stack --- OrderedCollection(Object)>>error: OrderedCollection>>errorNoSuchElement OrderedCollection>>at: [] in [] in SHParserST80>>parseKeyword - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Array(SequenceableCollection)>>do: [] in SHParserST80>>parseKeyword MethodContext(ContextPart)>>unwindTo: TerminateProcess>>signal TerminateProcess class>>signalForProcess:abandonedSemaphore: SystemDictionary(Set)>>do: SystemDictionary(Dictionary)>>associationsDo: SystemDictionary(Dictionary)>>keysDo: SystemDictionary(Dictionary)>>hasBindingThatBeginsWith: [] in SHParserST80>>resolvePartial: OrderedCollection>>do: SHParserST80>>resolvePartial: SHParserST80>>resolve: SHParserST80>>parseTerm [] in SHParserST80>>parseKeyword BlockClosure>>ensure: SHParserST80>>parseKeyword SHParserST80>>parseCascade SHParserST80>>parseExpression SHParserST80>>parseStatement SHParserST80>>parseStatementList [] in SHParserST80>>parse: BlockClosure>>ensure: SHParserST80>>parse: SHParserST80>>parse SHParserST80>>rangesIn:classOrMetaClass:workspace:environment: SHTextStylerST80>>rangesIn:setWorkspace: SHTextStylerST80>>privateStyle: [] in [] in SHTextStylerST80(SHTextStyler)>>styleInBackgroundProcess: [] in BlockClosure>>newProcess -- Best regards, Igor Stasenko AKA sig.