diff --git a/repository/OpenPonk-Model/OPAnnouncableObject.class.st b/repository/OpenPonk-Model/OPAnnouncableObject.class.st
index c90dd56..2086dab 100644
--- a/repository/OpenPonk-Model/OPAnnouncableObject.class.st
+++ b/repository/OpenPonk-Model/OPAnnouncableObject.class.st
@@ -44,13 +44,8 @@ OPAnnouncableObject >> announceRemoved: anElement [
 
 { #category : 'accessing' }
 OPAnnouncableObject >> announcer [
-	announcer ifNil: [ self announcer: Announcer new ].
-	^ announcer
-]
 
-{ #category : 'accessing' }
-OPAnnouncableObject >> announcer: anAnnouncer [
-	announcer := anAnnouncer
+	^ announcer ifNil: [ announcer := Announcer new ]
 ]
 
 { #category : 'announcing' }
@@ -78,6 +73,21 @@ OPAnnouncableObject >> unsubscribe: anObject [
 	^ self announcer unsubscribe: anObject
 ]
 
+{ #category : 'announcement registration' }
+OPAnnouncableObject >> weakWhen: anAnnouncementClass send: aSelector to: aReceiver [
+
+	^ self announcer weak
+		  when: anAnnouncementClass
+		  send: aSelector
+		  to: aReceiver
+]
+
+{ #category : 'announcement registration' }
+OPAnnouncableObject >> weakWhenChangedSend: aSelector to: aReceiver [
+
+	^ self weakWhen: OPElementChanged send: aSelector to: aReceiver
+]
+
 { #category : 'announcement registration' }
 OPAnnouncableObject >> when: anAnnouncementClass do: aValuable [
 
diff --git a/repository/OpenPonk-Model/OPModelObject.class.st b/repository/OpenPonk-Model/OPModelObject.class.st
index c85105e..119597d 100644
--- a/repository/OpenPonk-Model/OPModelObject.class.st
+++ b/repository/OpenPonk-Model/OPModelObject.class.st
@@ -28,7 +28,7 @@ OPModelObject >> add: anElement [
 	(elements includes: anElement) ifTrue: [ ^ anElement ].
 	anElement addedTo: self.
 	elements add: anElement.
-	anElement when: OPElementChanged send: #changed to: self.
+	anElement weakWhen: OPElementChanged send: #changed to: self.
 	self announceAdded: anElement.
 	^ anElement
 ]
@@ -140,7 +140,6 @@ OPModelObject >> remove [
 OPModelObject >> remove: anElement [
 
 	(elements includes: anElement) ifFalse: [ ^ anElement ].
-	anElement unsubscribe: self.
 	anElement removeFrom: self.
 	elements remove: anElement.
 	self announceRemoved: anElement.