diff --git a/repository/OpenPonk-ClassEditor/OPTUmlBaseController.trait.st b/repository/OpenPonk-ClassEditor/OPTUmlBaseController.trait.st
index cef7a188..7a301efc 100644
--- a/repository/OpenPonk-ClassEditor/OPTUmlBaseController.trait.st
+++ b/repository/OpenPonk-ClassEditor/OPTUmlBaseController.trait.st
@@ -88,15 +88,35 @@ OPTUmlBaseController >> descriptionVisibility [
 OPTUmlBaseController >> validateProperty: aProperty [
 
 	aProperty ifNil: [ ^ self ].
-	aProperty owningClass
+	(aProperty association isNotNil and: [
+		 (aProperty respondsTo: #oclIsKindOf:) not or: [
+			 aProperty oclIsKindOf: #Classifier ] ]) ifTrue: [
+		self validationFailedAssociationPropertyWithoutClassifierType:
+			aProperty ].
+	aProperty owningAssociation
 		ifNil: [
-			aProperty owningAssociation ifNil: [
+			aProperty owningClass ifNil: [
 				self validationFailedPropertyWithoutOwner: aProperty ] ]
 		ifNotNil: [
-			aProperty owningAssociation ifNotNil: [
+			aProperty owningClass ifNotNil: [
 				self validationFailedPropertyWithTwoOwners: aProperty ] ]
 ]
 
+{ #category : 'validation' }
+OPTUmlBaseController >> validationFailedAssociationPropertyWithoutClassifierType: aProperty [
+
+	OPModelInvalid signal: (String streamContents: [ :s |
+			 s << 'Property "' << aProperty name asString << '" has type '
+			 << aProperty type asString << ' although it is part of '
+			 << aProperty association asString ]).
+
+	"Try to use opposite owningClass as type"
+	aProperty opposite owningClass ifNotNil: [ :oppositeOwner |
+		aProperty type: oppositeOwner ]
+
+	"No way to fix this - the association end information is lost"
+]
+
 { #category : 'validation' }
 OPTUmlBaseController >> validationFailedPropertyWithTwoOwners: aProperty [
 
diff --git a/repository/OpenPonk-ClassEditor/OPUmlAttributeController.class.st b/repository/OpenPonk-ClassEditor/OPUmlAttributeController.class.st
index 5576d89a..f434e9af 100644
--- a/repository/OpenPonk-ClassEditor/OPUmlAttributeController.class.st
+++ b/repository/OpenPonk-ClassEditor/OPUmlAttributeController.class.st
@@ -140,17 +140,27 @@ OPUmlAttributeController >> descriptionMultiplicity [
 OPUmlAttributeController >> descriptionType [
 
 	<magritteDescription>
-	^ MAStringDescription new
-		  accessor: (MAPluggableAccessor
-				   read: [ :me | me model type ifNil: [ '' ] ifNotNil: #name ]
-				   write: [ :me :newValue |
-					   newValue
-						   ifEmpty: [ me model type: nil ]
-						   ifNotEmpty: [ me model type: (self typeNamed: newValue) ].
-					   self modelChanged ]);
-		  label: 'Type';
-		  priority: 5;
-		  yourself
+	| description writeBlock |
+	description := MAStringDescription new.
+	writeBlock := self model association
+		              ifNotNil: [
+			              description beReadOnly.
+			              [ :me :newValue |  ] ]
+		              ifNil: [
+			              [ :me :newValue |
+			              newValue
+				              ifEmpty: [ me model type: nil ]
+				              ifNotEmpty: [
+				              me model type: (self typeNamed: newValue) ].
+			              self modelChanged ] ].
+	description
+		accessor: (MAPluggableAccessor
+				 read: [ :me |
+					 me model type ifNil: [ '' ] ifNotNil: [ :type | type name ] ]
+				 write: writeBlock);
+		label: 'Type';
+		priority: 5.
+	^ description
 ]
 
 { #category : 'figures' }
diff --git a/repository/OpenPonk-ClassEditor/OPUmlPropertyMagritteDescriptions.class.st b/repository/OpenPonk-ClassEditor/OPUmlPropertyMagritteDescriptions.class.st
index e6c1d810..8727c91a 100644
--- a/repository/OpenPonk-ClassEditor/OPUmlPropertyMagritteDescriptions.class.st
+++ b/repository/OpenPonk-ClassEditor/OPUmlPropertyMagritteDescriptions.class.st
@@ -180,16 +180,19 @@ OPUmlPropertyMagritteDescriptions >> descriptionName [
 
 { #category : 'descriptions' }
 OPUmlPropertyMagritteDescriptions >> descriptionType [
+
 	<magritteDescription>
 	^ MAStringDescription new
-		beReadOnly;
-		accessor:
-			(MAPluggableAccessor
-				read: [ :me | (reader value: me) type name ]
-				write: [ :me :newValue |  ]);
-		label: labelPrefix;
-		priority: 1;
-		yourself
+		  beReadOnly;
+		  accessor: (MAPluggableAccessor
+				   read: [ :me |
+					   (reader value: me) type
+						   ifNil: [ '' ]
+						   ifNotNil: [ :type | type name ] ]
+				   write: [ :me :newValue |  ]);
+		  label: labelPrefix;
+		  priority: 1;
+		  yourself
 ]
 
 { #category : 'descriptions' }