diff --git a/repository/BaselineOfOpenPonk/BaselineOfOpenPonk.class.st b/repository/BaselineOfOpenPonk/BaselineOfOpenPonk.class.st
index 23d64d9c..9bb994b2 100644
--- a/repository/BaselineOfOpenPonk/BaselineOfOpenPonk.class.st
+++ b/repository/BaselineOfOpenPonk/BaselineOfOpenPonk.class.st
@@ -47,7 +47,7 @@ BaselineOfOpenPonk >> externalProjectsBaseline: spec [
 
 	spec baseline: 'Magritte' with: [
 		spec
-			repository: 'github://JanBliznicenko/magritte:master';
+			repository: 'github://magritte-metamodel/magritte:b24afda';
 			loads: #( Core 'Magritte-Morph' ) ].
 
 	spec
diff --git a/repository/OpenPonk-Core/MAContainer.extension.st b/repository/OpenPonk-Core/MAContainer.extension.st
new file mode 100644
index 00000000..94172b7c
--- /dev/null
+++ b/repository/OpenPonk-Core/MAContainer.extension.st
@@ -0,0 +1,13 @@
+Extension { #name : #MAContainer }
+
+{ #category : #'*OpenPonk-Core' }
+MAContainer >> definingContext [
+	
+	^ self propertyAt: #definingContext ifAbsent: [ nil ]
+]
+
+{ #category : #'*OpenPonk-Core' }
+MAContainer >> definingContext: anMADefiningContext [
+	
+	^ self propertyAt: #definingContext  put: anMADefiningContext
+]