Loading your cs gave me the following error:

MessageNotUnderstood: hasExtension
11 August 2003 7:33:59 pm

VM: unix - Squeak3.4 of 1 March 2003 [latest update: #5170]
Image: Squeak3.5 [latest update: #5180]

NewHandleMorph(Object)>>doesNotUnderstand:
	Receiver: a NewHandleMorph(2806)
	Arguments and temporary variables: 
		aMessage: 	a Message with selector: #hasExtension and arguments: #()
	Receiver's instance variables: 
		bounds: 	447 at 365 corner: 455 at 373
		owner: 	nil
		submorphs: 	#()
		fullBounds: 	447 at 365 corner: 455 at 373
		color: 	Color transparent
		extension: 	a MorphExtension (2354) [other:  (sensorMode -> true)]
		borderWidth: 	0
		borderColor: 	Color black
		pointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		lastPointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		hand: 	a HandMorph(3216)
		offset: 	nil
		waitingForClickInside: 	true

NewHandleMorph(Morph)>>delete
	Receiver: a NewHandleMorph(2806)
	Arguments and temporary variables: 
		aWorld: 	a PasteUpMorph(1622) [world]
		h: 	a HandMorph(3216)
	Receiver's instance variables: 
		bounds: 	447 at 365 corner: 455 at 373
		owner: 	nil
		submorphs: 	#()
		fullBounds: 	447 at 365 corner: 455 at 373
		color: 	Color transparent
		extension: 	a MorphExtension (2354) [other:  (sensorMode -> true)]
		borderWidth: 	0
		borderColor: 	Color black
		pointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		lastPointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		hand: 	a HandMorph(3216)
		offset: 	nil
		waitingForClickInside: 	true

NewHandleMorph>>delete
	Receiver: a NewHandleMorph(2806)
	Arguments and temporary variables: 

	Receiver's instance variables: 
		bounds: 	447 at 365 corner: 455 at 373
		owner: 	nil
		submorphs: 	#()
		fullBounds: 	447 at 365 corner: 455 at 373
		color: 	Color transparent
		extension: 	a MorphExtension (2354) [other:  (sensorMode -> true)]
		borderWidth: 	0
		borderColor: 	Color black
		pointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		lastPointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		hand: 	a HandMorph(3216)
		offset: 	nil
		waitingForClickInside: 	true

NewHandleMorph>>step
	Receiver: a NewHandleMorph(2806)
	Arguments and temporary variables: 
		eventSource: 	an EventSensor
	Receiver's instance variables: 
		bounds: 	447 at 365 corner: 455 at 373
		owner: 	nil
		submorphs: 	#()
		fullBounds: 	447 at 365 corner: 455 at 373
		color: 	Color transparent
		extension: 	a MorphExtension (2354) [other:  (sensorMode -> true)]
		borderWidth: 	0
		borderColor: 	Color black
		pointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		lastPointBlock: 	[] in SystemWindow>>spawnReframeHandle:
		hand: 	a HandMorph(3216)
		offset: 	nil
		waitingForClickInside: 	true


--- The full stack ---
NewHandleMorph(Object)>>doesNotUnderstand:
NewHandleMorph(Morph)>>delete
NewHandleMorph>>delete
NewHandleMorph>>step
 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
NewHandleMorph(Morph)>>stepAt:
StepMessage(MorphicAlarm)>>value:
WorldState>>runLocalStepMethodsIn:
WorldState>>runStepMethodsIn:
PasteUpMorph>>runStepMethods
WorldState>>doOneCycleNowFor:
WorldState>>doOneCycleFor:
PasteUpMorph>>doOneCycle
[] in Project class>>spawnNewProcess
[] in BlockContext>>newProcess



Am Sonntag, 10. August 2003 19:01 schrieben Sie:
> Hi,
>
> The attached CS fixes various issues with Morph adding and removing the
> appropriate notifications. The attached test (which needs to go on top of 
[...]