Hi, Is this a known problem? Am I doing wrong? 
What can I do for the community?

'halt' in BlockContext behaves strangely Squeak3.7beta [latest update: #5948] on MacOSX10.3.4.
VM is Squeak3.7.3Beta4.app and just downloaded image.

Open workspace in new Morphic project and  printIt( or evaluate) next code give different results.
[ self halt. 1] value

No response(GUI still responds, but unstable. No Debugger appeared. No result printed.) .
GUI freeze(without debugLog. 0.0% CPU usage. cmnd-. has no effect).
Debugger open as I expected (when proceed, print 1 as result).

===== SqueakDebug.log
Halt
10 June 2004 10:26:11 am

VM: Mac OS - a SmalltalkImage
Image: Squeak3.7beta [latest update: #5948]

SecurityManager state:
Restricted: false
FileAccess: true
SocketAccess: true
Working Dir PBG4:Squeak3.7b-5948 Folder
Trusted Dir PBG4:Squeak3.7b-5948 Folder
Untrusted Dir foobar:tooBar:forSqueak:bogus

UndefinedObject(Object)>>halt
        Receiver: nil
        Arguments and temporary variables: 

        Receiver's instance variables: 
nil
[] in UndefinedObject>>DoIt {[:a :b |  self halt.  sum := a + b.  sum]}
        Arguments and temporary variables: 
                a:      1
                b:      2
                sum:    nil

UndefinedObject>>DoIt
        Receiver: nil
        Arguments and temporary variables: 
                a:      1
                b:      2
                sum:    nil
        Receiver's instance variables: 
nil
Compiler>>evaluate:in:to:notifying:ifFail:logged:
        Receiver: a Compiler
        Arguments and temporary variables: 
                textOrStream:   a ReadWriteStream '[ :a :b | |sum| self halt. sum _ a + b. sum] v...etc...
                aContext:       nil
                receiver:       nil
                aRequestor:     a TextMorphEditor
                failBlock:      [] in TextMorphEditor(ParagraphEditor)>>evaluateSelection {[FakeClas...etc...
                logFlag:        true
                methodNode:     DoIt
        ^ [:a :b | 
        | sum | 
        self halt.
        sum := a + b.
        sum]
                valu...etc...
                method:         a CompiledMethod (754)
                value:  nil
                selector:       #DoIt
        Receiver's instance variables: 
                sourceStream:   a ReadWriteStream '[ :a :b | |sum| self halt. sum _ a + b. sum] v...etc...
                requestor:      a TextMorphEditor
                class:  UndefinedObject
                context:        nil
                parserClass:    Parser
                cacheDoItNode:  true


--- The full stack ---
UndefinedObject(Object)>>halt
[] in UndefinedObject>>DoIt {[:a :b |  self halt.  sum := a + b.  sum]}
UndefinedObject>>DoIt
Compiler>>evaluate:in:to:notifying:ifFail:logged:
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[] in TextMorphEditor(ParagraphEditor)>>evaluateSelection {[rcvr class evaluatorClass new   evaluate: self selectionAsStream   in: ctxt...]}
BlockContext>>on:do:
TextMorphEditor(ParagraphEditor)>>evaluateSelection
TextMorphEditor(ParagraphEditor)>>printIt
[] in TextMorphEditor(ParagraphEditor)>>printIt: {[self printIt]}
TextMorphEditor(Controller)>>terminateAndInitializeAround:
TextMorphEditor(ParagraphEditor)>>printIt:
TextMorphEditor(ParagraphEditor)>>dispatchOnCharacter:with:
TextMorphEditor>>dispatchOnCharacter:with:
TextMorphEditor(ParagraphEditor)>>readKeyboard
TextMorphEditor>>readKeyboard
[] in TextMorphForEditView(TextMorph)>>keyStroke: {[editor readKeyboard]}
TextMorphForEditView(TextMorph)>>handleInteraction:fromEvent:
TextMorphForEditView>>handleInteraction:fromEvent:
TextMorphForEditView(TextMorph)>>keyStroke:
TextMorphForEditView>>keyStroke:
TextMorphForEditView(TextMorph)>>handleKeystroke:
KeyboardEvent>>sentTo:
TextMorphForEditView(Morph)>>handleEvent:
TextMorphForEditView(Morph)>>handleFocusEvent:
[] in HandMorph>>sendFocusEvent:to:clear: {[ActiveHand := self.  ActiveEvent := anEvent.  result := focusHolder     han...]}
[] in PasteUpMorph>>becomeActiveDuring: {[aBlock value]}
BlockContext>>on:do:
PasteUpMorph>>becomeActiveDuring:
HandMorph>>sendFocusEvent:to:clear:
HandMorph>>sendEvent:focus:clear:
HandMorph>>sendKeyboardEvent:
HandMorph>>handleEvent:
HandMorph>>processEvents
[] in WorldState>>doOneCycleNowFor: {[:h |  ActiveHand := h.  h processEvents.  capturingGesture := capturingGest...]}
Array(SequenceableCollection)>>do:
WorldState>>handsDo:
WorldState>>doOneCycleNowFor:
WorldState>>doOneCycleFor:
PasteUpMorph>>doOneCycle
[] in Project class>>spawnNewProcess {[[World doOneCycle.  Processor yield.  false] whileFalse.  nil]}
[] in BlockContext>>newProcess {[self value.  Processor terminateActive]}


-------------------------------
^. .^    Kouji Takahashi  <tako at aquilax.co.jp>
 ='=     Tel +81-3-3986-4834    Fax +81-3-5992-0792