In trunk, I get the following error report (see attachment) when creating a
PianoRollScoreMorph through "PianoRollScoreMorph new openInHand".
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1 February 2022 4:02:06.264525 pm

VM: unix - Smalltalk
Image: Squeak6.0alpha [latest update: #21120]

SecurityManager state:
Restricted: false
FileAccess: true
SocketAccess: true
Working Dir /home/dto/Squeak/shared
Trusted Dir /home/dto/Squeak/shared/secure
Untrusted Dir /home/dto/Squeak/shared/My Squeak

UndefinedObject(Object)>>doesNotUnderstand: #ticksPerQuarterNote
	Receiver: nil
	Arguments and temporary variables: 
		aMessage: 	ticksPerQuarterNote
		exception: 	MessageNotUnderstood: UndefinedObject>>ticksPerQuarterNote
		resumeValue: 	nil
	Receiver's instance variables: 
nil

PianoRollScoreMorph>>drawMeasureLinesOn:
	Receiver: a PianoRollScoreMorph(669861)
	Arguments and temporary variables: 
		aCanvas: 	a FormCanvas on: Form(400x300x32)
		ticksPerMeas: 	nil
		x: 	nil
		measureLineColor: 	(Color r: 0.7 g: 0.7 b: 0.7)
		inner: 	nil
	Receiver's instance variables: 
		bounds: 	1076 at 147 corner: 1476 at 447
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	1076 at 147 corner: 1476 at 447
		color: 	Color white
		extension: 	a MorphExtension (3739374) [other:  (errorOnDraw -> true) (clipSubmo...etc...
		borderWidth: 	1
		borderColor: 	Color black
		scorePlayer: 	nil
		score: 	nil
		colorForTrack: 	nil
		lowestNote: 	nil
		leftEdgeTime: 	nil
		timeScale: 	nil
		indexInTrack: 	nil
		lastUpdateTick: 	nil
		lastMutedState: 	nil
		cursor: 	nil
		selection: 	nil
		timeSignature: 	nil
		beatsPerMeasure: 	4
		notePerBeat: 	4
		showMeasureLines: 	true
		showBeatLines: 	false
		soundsPlaying: 	nil
		soundsPlayingMorph: 	nil
		movieClipPlayer: 	nil

PianoRollScoreMorph>>drawStaffOn:
	Receiver: a PianoRollScoreMorph(669861)
	Arguments and temporary variables: 
		aCanvas: 	a FormCanvas on: Form(400x300x32)
		blackKeyColor: 	nil
		l: 	nil
		r: 	nil
		topEdge: 	nil
		y: 	nil
		k: 	nil
	Receiver's instance variables: 
		bounds: 	1076 at 147 corner: 1476 at 447
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	1076 at 147 corner: 1476 at 447
		color: 	Color white
		extension: 	a MorphExtension (3739374) [other:  (errorOnDraw -> true) (clipSubmo...etc...
		borderWidth: 	1
		borderColor: 	Color black
		scorePlayer: 	nil
		score: 	nil
		colorForTrack: 	nil
		lowestNote: 	nil
		leftEdgeTime: 	nil
		timeScale: 	nil
		indexInTrack: 	nil
		lastUpdateTick: 	nil
		lastMutedState: 	nil
		cursor: 	nil
		selection: 	nil
		timeSignature: 	nil
		beatsPerMeasure: 	4
		notePerBeat: 	4
		showMeasureLines: 	true
		showBeatLines: 	false
		soundsPlaying: 	nil
		soundsPlayingMorph: 	nil
		movieClipPlayer: 	nil

PianoRollScoreMorph>>drawOn:
	Receiver: a PianoRollScoreMorph(669861)
	Arguments and temporary variables: 
		aCanvas: 	a FormCanvas on: Form(400x300x32)
	Receiver's instance variables: 
		bounds: 	1076 at 147 corner: 1476 at 447
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	1076 at 147 corner: 1476 at 447
		color: 	Color white
		extension: 	a MorphExtension (3739374) [other:  (errorOnDraw -> true) (clipSubmo...etc...
		borderWidth: 	1
		borderColor: 	Color black
		scorePlayer: 	nil
		score: 	nil
		colorForTrack: 	nil
		lowestNote: 	nil
		leftEdgeTime: 	nil
		timeScale: 	nil
		indexInTrack: 	nil
		lastUpdateTick: 	nil
		lastMutedState: 	nil
		cursor: 	nil
		selection: 	nil
		timeSignature: 	nil
		beatsPerMeasure: 	4
		notePerBeat: 	4
		showMeasureLines: 	true
		showBeatLines: 	false
		soundsPlaying: 	nil
		soundsPlayingMorph: 	nil
		movieClipPlayer: 	nil

FormCanvas(Canvas)>>draw:
	Receiver: a FormCanvas on: Form(400x300x32)
	Arguments and temporary variables: 
		anObject: 	a PianoRollScoreMorph(669861)
	Receiver's instance variables: 
		target: 	nil
		filterSelector: 	nil
		origin: 	-415@ -516
		clipRect: 	0 at 0 corner: 400 at 300
		form: 	Form(400x300x32)
		port: 	a GrafPort
		shadowColor: 	nil

FormCanvas(Canvas)>>drawMorph:
	Receiver: a FormCanvas on: Form(400x300x32)
	Arguments and temporary variables: 
		aMorph: 	a PianoRollScoreMorph(669861)
	Receiver's instance variables: 
		target: 	nil
		filterSelector: 	nil
		origin: 	-415@ -516
		clipRect: 	0 at 0 corner: 400 at 300
		form: 	Form(400x300x32)
		port: 	a GrafPort
		shadowColor: 	nil

PianoRollScoreMorph(Morph)>>fullDrawOn:
	Receiver: a PianoRollScoreMorph(669861)
	Arguments and temporary variables: 
		aCanvas: 	a FormCanvas on: Form(400x300x32)
	Receiver's instance variables: 
		bounds: 	1076 at 147 corner: 1476 at 447
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	1076 at 147 corner: 1476 at 447
		color: 	Color white
		extension: 	a MorphExtension (3739374) [other:  (errorOnDraw -> true) (clipSubmo...etc...
		borderWidth: 	1
		borderColor: 	Color black
		scorePlayer: 	nil
		score: 	nil
		colorForTrack: 	nil
		lowestNote: 	nil
		leftEdgeTime: 	nil
		timeScale: 	nil
		indexInTrack: 	nil
		lastUpdateTick: 	nil
		lastMutedState: 	nil
		cursor: 	nil
		selection: 	nil
		timeSignature: 	nil
		beatsPerMeasure: 	4
		notePerBeat: 	4
		showMeasureLines: 	true
		showBeatLines: 	false
		soundsPlaying: 	nil
		soundsPlayingMorph: 	nil
		movieClipPlayer: 	nil

FormCanvas(Canvas)>>fullDraw:
	Receiver: a FormCanvas on: Form(400x300x32)
	Arguments and temporary variables: 
		anObject: 	a PianoRollScoreMorph(669861)
	Receiver's instance variables: 
		target: 	nil
		filterSelector: 	nil
		origin: 	-415@ -516
		clipRect: 	0 at 0 corner: 400 at 300
		form: 	Form(400x300x32)
		port: 	a GrafPort
		shadowColor: 	nil

FormCanvas(Canvas)>>fullDrawMorph:
	Receiver: a FormCanvas on: Form(400x300x32)
	Arguments and temporary variables: 
		aMorph: 	a PianoRollScoreMorph(669861)
	Receiver's instance variables: 
		target: 	nil
		filterSelector: 	nil
		origin: 	-415@ -516
		clipRect: 	0 at 0 corner: 400 at 300
		form: 	Form(400x300x32)
		port: 	a GrafPort
		shadowColor: 	nil

[] in [] in HandMorph(Morph)>>drawSubmorphsOn:
	Receiver: a HandMorph(1270677)
	Arguments and temporary variables: 
		aCanvas: 	a FormCanvas on: Form(400x300x32)
		drawBlock: 	nil
		canvas: 	a FormCanvas on: Form(400x300x32)
		m: 	a PianoRollScoreMorph(669861)
	Receiver's instance variables: 
		bounds: 	499 at 403 corner: 515 at 419
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	499 at 403 corner: 515 at 419
		color: 	Color blue
		extension: 	a MorphExtension (1885061) [other:  (balloonHelpMorphs -> an Ordered...etc...
		mouseFocus: 	nil
		keyboardFocus: 	a PluggableListMorphPlus(707416)
		eventListeners: 	nil
		mouseListeners: 	nil
		keyboardListeners: 	a WeakArray(a KeyStrip(2449763))
		eventCaptureFilters: 	nil
		mouseCaptureFilters: 	nil
		keyboardCaptureFilters: 	a WeakArray(a HandMorph(1270677))
		mouseClickState: 	nil
		mouseOverHandler: 	a MouseOverHandler
		targetOffset: 	110 at 13
		lastMouseEvent: 	[499 at 403 mouseUp ( red ) 11425778]
		lastKeyDownEvent: 	[805 at 293 keyDown (250) 11318180]
		damageRecorder: 	a DamageRecorder
		cacheCanvas: 	nil
		cachedCanvasHasHoles: 	false
		temporaryCursor: 	nil
		temporaryCursorOffset: 	nil
		hardwareCursor: 	nil
		hasChanged: 	true
		savedPatch: 	nil
		userInitials: 	''
		lastEventBuffer: 	#(1 11425778 499 403 0 0 0 1)
		genieGestureProcessor: 	nil
		keyboardInterpreter: 	an UTF32InputInterpreter
		externalDropMorph: 	nil

Array(SequenceableCollection)>>reverseDo:
	Receiver: {a PianoRollScoreMorph(669861)}
	Arguments and temporary variables: 
		aBlock: 	[closure] in [] in HandMorph(Morph)>>drawSubmorphsOn:
		index: 	1
	Receiver's instance variables: 
{a PianoRollScoreMorph(669861)}

[] in HandMorph(Morph)>>drawSubmorphsOn:
	Receiver: a HandMorph(1270677)
	Arguments and temporary variables: 
		aCanvas: 	a FormCanvas on: Form(400x300x32)
		drawBlock: 	nil
		canvas: 	a FormCanvas on: Form(400x300x32)
	Receiver's instance variables: 
		bounds: 	499 at 403 corner: 515 at 419
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	499 at 403 corner: 515 at 419
		color: 	Color blue
		extension: 	a MorphExtension (1885061) [other:  (balloonHelpMorphs -> an Ordered...etc...
		mouseFocus: 	nil
		keyboardFocus: 	a PluggableListMorphPlus(707416)
		eventListeners: 	nil
		mouseListeners: 	nil
		keyboardListeners: 	a WeakArray(a KeyStrip(2449763))
		eventCaptureFilters: 	nil
		mouseCaptureFilters: 	nil
		keyboardCaptureFilters: 	a WeakArray(a HandMorph(1270677))
		mouseClickState: 	nil
		mouseOverHandler: 	a MouseOverHandler
		targetOffset: 	110 at 13
		lastMouseEvent: 	[499 at 403 mouseUp ( red ) 11425778]
		lastKeyDownEvent: 	[805 at 293 keyDown (250) 11318180]
		damageRecorder: 	a DamageRecorder
		cacheCanvas: 	nil
		cachedCanvasHasHoles: 	false
		temporaryCursor: 	nil
		temporaryCursorOffset: 	nil
		hardwareCursor: 	nil
		hasChanged: 	true
		savedPatch: 	nil
		userInitials: 	''
		lastEventBuffer: 	#(1 11425778 499 403 0 0 0 1)
		genieGestureProcessor: 	nil
		keyboardInterpreter: 	an UTF32InputInterpreter
		externalDropMorph: 	nil

HandMorph(Morph)>>drawSubmorphsOn:
	Receiver: a HandMorph(1270677)
	Arguments and temporary variables: 
		aCanvas: 	a FormCanvas on: Form(400x300x32)
		drawBlock: 	[closure] in HandMorph(Morph)>>drawSubmorphsOn:
	Receiver's instance variables: 
		bounds: 	499 at 403 corner: 515 at 419
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	499 at 403 corner: 515 at 419
		color: 	Color blue
		extension: 	a MorphExtension (1885061) [other:  (balloonHelpMorphs -> an Ordered...etc...
		mouseFocus: 	nil
		keyboardFocus: 	a PluggableListMorphPlus(707416)
		eventListeners: 	nil
		mouseListeners: 	nil
		keyboardListeners: 	a WeakArray(a KeyStrip(2449763))
		eventCaptureFilters: 	nil
		mouseCaptureFilters: 	nil
		keyboardCaptureFilters: 	a WeakArray(a HandMorph(1270677))
		mouseClickState: 	nil
		mouseOverHandler: 	a MouseOverHandler
		targetOffset: 	110 at 13
		lastMouseEvent: 	[499 at 403 mouseUp ( red ) 11425778]
		lastKeyDownEvent: 	[805 at 293 keyDown (250) 11318180]
		damageRecorder: 	a DamageRecorder
		cacheCanvas: 	nil
		cachedCanvasHasHoles: 	false
		temporaryCursor: 	nil
		temporaryCursorOffset: 	nil
		hardwareCursor: 	nil
		hasChanged: 	true
		savedPatch: 	nil
		userInitials: 	''
		lastEventBuffer: 	#(1 11425778 499 403 0 0 0 1)
		genieGestureProcessor: 	nil
		keyboardInterpreter: 	an UTF32InputInterpreter
		externalDropMorph: 	nil

[] in HandMorph>>updateCacheCanvas:
	Receiver: a HandMorph(1270677)
	Arguments and temporary variables: 
		aCanvas: 	an AnimFormCanvas on: DisplayScreen(1920x1050x32)
		subBnds: 	nil
		rectList: 	nil
		nPix: 	nil
		tempCanvas: 	a FormCanvas on: Form(400x300x32)
	Receiver's instance variables: 
		bounds: 	499 at 403 corner: 515 at 419
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	499 at 403 corner: 515 at 419
		color: 	Color blue
		extension: 	a MorphExtension (1885061) [other:  (balloonHelpMorphs -> an Ordered...etc...
		mouseFocus: 	nil
		keyboardFocus: 	a PluggableListMorphPlus(707416)
		eventListeners: 	nil
		mouseListeners: 	nil
		keyboardListeners: 	a WeakArray(a KeyStrip(2449763))
		eventCaptureFilters: 	nil
		mouseCaptureFilters: 	nil
		keyboardCaptureFilters: 	a WeakArray(a HandMorph(1270677))
		mouseClickState: 	nil
		mouseOverHandler: 	a MouseOverHandler
		targetOffset: 	110 at 13
		lastMouseEvent: 	[499 at 403 mouseUp ( red ) 11425778]
		lastKeyDownEvent: 	[805 at 293 keyDown (250) 11318180]
		damageRecorder: 	a DamageRecorder
		cacheCanvas: 	nil
		cachedCanvasHasHoles: 	false
		temporaryCursor: 	nil
		temporaryCursorOffset: 	nil
		hardwareCursor: 	nil
		hasChanged: 	true
		savedPatch: 	nil
		userInitials: 	''
		lastEventBuffer: 	#(1 11425778 499 403 0 0 0 1)
		genieGestureProcessor: 	nil
		keyboardInterpreter: 	an UTF32InputInterpreter
		externalDropMorph: 	nil

FormCanvas>>translateBy:during:
	Receiver: a FormCanvas on: Form(400x300x32)
	Arguments and temporary variables: 
		delta: 	-415@ -516
		aBlock: 	[closure] in HandMorph>>updateCacheCanvas:
	Receiver's instance variables: 
		target: 	nil
		filterSelector: 	nil
		origin: 	0 at 0
		clipRect: 	0 at 0 corner: 400 at 300
		form: 	Form(400x300x32)
		port: 	a GrafPort
		shadowColor: 	nil

HandMorph>>updateCacheCanvas:
	Receiver: a HandMorph(1270677)
	Arguments and temporary variables: 
		aCanvas: 	an AnimFormCanvas on: DisplayScreen(1920x1050x32)
		subBnds: 	415 at 516 corner: 815 at 816
		rectList: 	an OrderedCollection(123 at 26 corner: 1072 at 1043)
		nPix: 	nil
	Receiver's instance variables: 
		bounds: 	499 at 403 corner: 515 at 419
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	499 at 403 corner: 515 at 419
		color: 	Color blue
		extension: 	a MorphExtension (1885061) [other:  (balloonHelpMorphs -> an Ordered...etc...
		mouseFocus: 	nil
		keyboardFocus: 	a PluggableListMorphPlus(707416)
		eventListeners: 	nil
		mouseListeners: 	nil
		keyboardListeners: 	a WeakArray(a KeyStrip(2449763))
		eventCaptureFilters: 	nil
		mouseCaptureFilters: 	nil
		keyboardCaptureFilters: 	a WeakArray(a HandMorph(1270677))
		mouseClickState: 	nil
		mouseOverHandler: 	a MouseOverHandler
		targetOffset: 	110 at 13
		lastMouseEvent: 	[499 at 403 mouseUp ( red ) 11425778]
		lastKeyDownEvent: 	[805 at 293 keyDown (250) 11318180]
		damageRecorder: 	a DamageRecorder
		cacheCanvas: 	nil
		cachedCanvasHasHoles: 	false
		temporaryCursor: 	nil
		temporaryCursorOffset: 	nil
		hardwareCursor: 	nil
		hasChanged: 	true
		savedPatch: 	nil
		userInitials: 	''
		lastEventBuffer: 	#(1 11425778 499 403 0 0 0 1)
		genieGestureProcessor: 	nil
		keyboardInterpreter: 	an UTF32InputInterpreter
		externalDropMorph: 	nil

HandMorph>>fullDrawOn:
	Receiver: a HandMorph(1270677)
	Arguments and temporary variables: 
		aCanvas: 	an AnimFormCanvas on: DisplayScreen(1920x1050x32)
		disableCaching: 	false
		subBnds: 	415 at 516 corner: 815 at 816
	Receiver's instance variables: 
		bounds: 	499 at 403 corner: 515 at 419
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	499 at 403 corner: 515 at 419
		color: 	Color blue
		extension: 	a MorphExtension (1885061) [other:  (balloonHelpMorphs -> an Ordered...etc...
		mouseFocus: 	nil
		keyboardFocus: 	a PluggableListMorphPlus(707416)
		eventListeners: 	nil
		mouseListeners: 	nil
		keyboardListeners: 	a WeakArray(a KeyStrip(2449763))
		eventCaptureFilters: 	nil
		mouseCaptureFilters: 	nil
		keyboardCaptureFilters: 	a WeakArray(a HandMorph(1270677))
		mouseClickState: 	nil
		mouseOverHandler: 	a MouseOverHandler
		targetOffset: 	110 at 13
		lastMouseEvent: 	[499 at 403 mouseUp ( red ) 11425778]
		lastKeyDownEvent: 	[805 at 293 keyDown (250) 11318180]
		damageRecorder: 	a DamageRecorder
		cacheCanvas: 	nil
		cachedCanvasHasHoles: 	false
		temporaryCursor: 	nil
		temporaryCursorOffset: 	nil
		hardwareCursor: 	nil
		hasChanged: 	true
		savedPatch: 	nil
		userInitials: 	''
		lastEventBuffer: 	#(1 11425778 499 403 0 0 0 1)
		genieGestureProcessor: 	nil
		keyboardInterpreter: 	an UTF32InputInterpreter
		externalDropMorph: 	nil

HandMorph(Morph)>>fullDrawAnimatedOn:
	Receiver: a HandMorph(1270677)
	Arguments and temporary variables: 
		aCanvas: 	an AnimFormCanvas on: DisplayScreen(1920x1050x32)
		transformedCanvas: 	an AnimFormCanvas on: DisplayScreen(1920x1050x32)
	Receiver's instance variables: 
		bounds: 	499 at 403 corner: 515 at 419
		owner: 	a PasteUpMorph(3166923) [world]
		submorphs: 	#()
		fullBounds: 	499 at 403 corner: 515 at 419
		color: 	Color blue
		extension: 	a MorphExtension (1885061) [other:  (balloonHelpMorphs -> an Ordered...etc...
		mouseFocus: 	nil
		keyboardFocus: 	a PluggableListMorphPlus(707416)
		eventListeners: 	nil
		mouseListeners: 	nil
		keyboardListeners: 	a WeakArray(a KeyStrip(2449763))
		eventCaptureFilters: 	nil
		mouseCaptureFilters: 	nil
		keyboardCaptureFilters: 	a WeakArray(a HandMorph(1270677))
		mouseClickState: 	nil
		mouseOverHandler: 	a MouseOverHandler
		targetOffset: 	110 at 13
		lastMouseEvent: 	[499 at 403 mouseUp ( red ) 11425778]
		lastKeyDownEvent: 	[805 at 293 keyDown (250) 11318180]
		damageRecorder: 	a DamageRecorder
		cacheCanvas: 	nil
		cachedCanvasHasHoles: 	false
		temporaryCursor: 	nil
		temporaryCursorOffset: 	nil
		hardwareCursor: 	nil
		hasChanged: 	true
		savedPatch: 	nil
		userInitials: 	''
		lastEventBuffer: 	#(1 11425778 499 403 0 0 0 1)
		genieGestureProcessor: 	nil
		keyboardInterpreter: 	an UTF32InputInterpreter
		externalDropMorph: 	nil

AnimFormCanvas>>fullDrawMorph:
	Receiver: an AnimFormCanvas on: DisplayScreen(1920x1050x32)
	Arguments and temporary variables: 
		aMorph: 	a HandMorph(1270677)
	Receiver's instance variables: 
		target: 	nil
		filterSelector: 	nil
		origin: 	0 at 0
		clipRect: 	0 at 0 corner: 1920 at 1050
		form: 	DisplayScreen(1920x1050x32)
		port: 	a GrafPort
		shadowColor: 	nil


--- The full stack ---
UndefinedObject(Object)>>doesNotUnderstand: #ticksPerQuarterNote
PianoRollScoreMorph>>drawMeasureLinesOn:
PianoRollScoreMorph>>drawStaffOn:
PianoRollScoreMorph>>drawOn:
FormCanvas(Canvas)>>draw:
FormCanvas(Canvas)>>drawMorph:
PianoRollScoreMorph(Morph)>>fullDrawOn:
FormCanvas(Canvas)>>fullDraw:
FormCanvas(Canvas)>>fullDrawMorph:
[] in [] in HandMorph(Morph)>>drawSubmorphsOn:
Array(SequenceableCollection)>>reverseDo:
[] in HandMorph(Morph)>>drawSubmorphsOn:
HandMorph(Morph)>>drawSubmorphsOn:
[] in HandMorph>>updateCacheCanvas:
FormCanvas>>translateBy:during:
HandMorph>>updateCacheCanvas:
HandMorph>>fullDrawOn:
HandMorph(Morph)>>fullDrawAnimatedOn:
AnimFormCanvas>>fullDrawMorph:
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[] in AnimWorldState(WorldState)>>displayWorld:submorphs:
OrderedCollection>>reverseDo:
AnimWorldState(WorldState)>>displayWorld:submorphs:
PasteUpMorph>>privateOuterDisplayWorld
PasteUpMorph>>displayWorld
[] in AnimWorldState(WorldState)>>displayWorldSafely:
FullBlockClosure(BlockClosure)>>on:do:
AnimWorldState(WorldState)>>displayWorldSafely:
AnimWorldState(WorldState)>>doOneCycleNowFor:
AnimWorldState(WorldState)>>doOneCycleFor:
PasteUpMorph>>doOneCycle
[] in AnimMorphicProject>>spawnNewProcess
[] in FullBlockClosure(BlockClosure)>>newProcess