This is definitely a bug. But it does work in individual playfields. 
See if this is a good enough work around for now.

Cheers,

Alan

At 08:39 AM 6/4/2007, narayans at uncw.edu wrote:
>I turned on the graph paper in the world, and then tried to open a
>viewer on the world.
>
>4 June 2007 11:37:04 am
>
>VM: Win32 - a SmalltalkImage
>Image: OLPC2.0 [latest update: #1349]
>
>SecurityManager state:
>Restricted: false
>FileAccess: true
>SocketAccess: true
>Working Dir C:\My Squeak\narayans
>Trusted Dir C:\olpc-E-Toys\narayans
>Untrusted Dir C:\My Squeak\narayans
>
>InfiniteForm(Object)>>doesNotUnderstand: #red
>         Receiver: an InfiniteForm
>         Arguments and temporary variables:
>                 t1:     red
>         Receiver's instance variables:
>                 patternForm:    Form(16x16x16)
>
>UnscriptedPlayer(Player)>>getRed
>         Receiver: an UnscriptedPlayer (3407) named world
>         Arguments and temporary variables:
>
>         Receiver's instance variables:
>                 dependents:     nil
>                 costume:        a PasteUpMorph<world>(1622) [world]
>                 costumes:       nil
>
>NumberType(DataType)>>updatingTileForTarget:partName:getter:setter:
>         Receiver: a NumberType named "Number"
>         Arguments and temporary variables:
>                 aTarget:        an UnscriptedPlayer (3407) named world
>                 partName:       #getRed
>                 getter:         #getRed
>                 setter:         #setRed:
>                 aTile:  a NumericReadoutTile(2801) - #literal op= ''
>                 displayer:      an UpdatingStringMorph<readout 
> string>(3696)nil
>                 actualSetter:   #setRed:
>         Receiver's instance variables:
>                 authoringStamp:         ' 2/16/2007 17:09'
>                 properties:     a Dictionary(#helpMessage->'Numbers 
> are things that can
>do arithmet...etc...
>                 elementSymbol:  nil
>                 naturalLanguageTranslations:    nil
>                 vocabularyName:         #Number
>                 categories:     an OrderedCollection(an 
> ElementCategory named comparing
>an ElementC...etc...
>                 methodInterfaces:       an 
> IdentityDictionary(#abs->a MethodInterface -
>wording: #abs...etc...
>                 object:         nil
>                 limitClass:     nil
>                 translationTable:       nil
>
>CategoryViewer>>readoutFor:type:readOnly:getSelector:putSelector:
>         Receiver: a CategoryViewer(2912)
>         Arguments and temporary variables:
>                 t1:     #getRed
>                 t2:     #Number
>                 t3:     false
>                 t4:     #getRed
>                 t5:     #setRed:
>                 t6:     nil
>                 t7:     nil
>         Receiver's instance variables:
>                 bounds:         0 at 0 corner: 50 at 40
>                 owner:  nil
>                 submorphs:      #(an AlignmentMorph(3081))
>                 fullBounds:     nil
>                 color:  (Color r: 0.946 g: 1.0 b: 0.946)
>                 extension:      a MorphExtensionPlus (3364) 
> [sticky]  [layoutPolicy -
>TableLayout]  ...etc...
>                 borderWidth:    0
>                 borderColor:    (Color r: 0.5 g: 0.7 b: 0.5)
>                 scriptedPlayer:         an UnscriptedPlayer (3407) 
> named world
>                 namePane:       a BorderedMorph(2015)
>                 chosenCategorySymbol:   #color
>
>
>--- The full stack ---
>InfiniteForm(Object)>>doesNotUnderstand: #red
>UnscriptedPlayer(Player)>>getRed
>NumberType(DataType)>>updatingTileForTarget:partName:getter:setter:
>CategoryViewer>>readoutFor:type:readOnly:getSelector:putSelector:
>  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>CategoryViewer>>phraseForVariableFrom:
>[] in UnscriptedPlayer(Object)>>tilePhrasesForMethodInterfaces:inViewer:
>{[:aMethodInterface | ((resultType := aMethodInterface resultType)
>notNil    ...]}
>Array(SequenceableCollection)>>collect:
>UnscriptedPlayer(Object)>>tilePhrasesForMethodInterfaces:inViewer:
>UnscriptedPlayer(Object)>>tilePhrasesForCategory:inViewer:
>CategoryViewer>>categoryWording:
>CategoryViewer>>chosenCategorySymbol:
>CategoryViewer>>chooseCategoryWhoseTranslatedWordingIs:
>CategoryViewer>>initializeFor:categoryChoice:
>StandardViewer>>categoryViewerFor:
>[] in StandardViewer>>addCategoryViewerFor:atEnd: {[aViewer := self
>categoryViewerFor: categoryInfo.  atEnd   ifTrue: [self add...]}
>BlockContext>>ensure:
>CursorWithMask(Cursor)>>showWhile:
>StandardViewer>>addCategoryViewerFor:atEnd:
>StandardViewer>>addCategoryViewerFor:
>StandardViewer>>addCategoryViewer
>StandardViewer>>initializeFor:barHeight:includeDismissButton:showCategor
>ies:
>StandardViewer>>initializeFor:barHeight:includeDismissButton:
>StandardViewer>>initializeFor:barHeight:
>Presenter>>viewMorph:
>[] in PasteUpMorph(Morph)>>openViewerForArgument {[self presenter
>viewMorph: self]}
>BlockContext>>ensure:
>CursorWithMask(Cursor)>>showWhile:
>PasteUpMorph(Morph)>>openViewerForArgument
>HaloMorph>>openViewerForTarget:with:
>EventHandler>>send:to:withEvent:fromMorph:
>EventHandler>>mouseDown:fromMorph:
>ThreePhaseButtonMorph(Morph)>>mouseDown:
>ThreePhaseButtonMorph>>mouseDown:
>ThreePhaseButtonMorph(Morph)>>handleMouseDown:
>MouseButtonEvent>>sentTo:
>ThreePhaseButtonMorph(Morph)>>handleEvent:
>MorphicEventDispatcher>>dispatchMouseDown:with:
>MorphicEventDispatcher>>dispatchEvent:with:
>ThreePhaseButtonMorph(Morph)>>processEvent:using:
>...etc...