diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractBaseDiagram.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractBaseDiagram.xtend
index e1abb79..02ee746 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractBaseDiagram.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractBaseDiagram.xtend
@@ -48,12 +48,12 @@ abstract class AbstractBaseDiagram<T extends DiagramDescription> extends Abstrac
 	 * @param descrLabel displayed on representation groups
 	 * @param domain class of diagram
 	 */
-	new(Class<T> type, SiriusVpGroup parent, String descrLabel, Class<? extends EObject> domain) {
-		super(type, parent, descrLabel)
+	new(Class<T> type, SiriusVpGroup parent, String label, Class<? extends EObject> domain) {
+		super(type, parent, label)
 		
 		this.domain = domain
 		creationTasks.add[
-			domainClass = context.asDomainClass(domain)
+			domainClass = domain.asDomainClass
 		]
 	}
 		
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractDiagramPart.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractDiagramPart.xtend
index 844c00f..f268a5b 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractDiagramPart.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractDiagramPart.xtend
@@ -107,7 +107,8 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	}
 	
 	public static val STYLE = StylePackage.eINSTANCE
-	public static val DSTYLE = org.eclipse.sirius.diagram.description.style.StylePackage.eINSTANCE
+	public static val DSTYLE = org.eclipse.sirius.diagram.description.style
+			.StylePackage.eINSTANCE
 	
 	/**
 	 * Creates a factory for a diagram description
@@ -145,7 +146,7 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	 * @param type of the description
 	 */
 	def void setDomainClass(AbstractNodeMapping it, Class<? extends EObject> type) {
-		domainClass = context.asEClass(type) as EClass
+		domainClass = type.asEClass
 	}
 
 	/**
@@ -161,7 +162,6 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 		domainClass = SiriusDesigns.encode(type)
 	}
 
-
 	/**
 	 * Sets the domain class of a mapping.
 	 * <p>
@@ -172,7 +172,7 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	 * @param type of the description
 	 */
 	def void setDomainClass(EdgeMapping it, Class<? extends EObject> type) {
-		domainClass = context.asEClass(type) as EClass
+		domainClass = type.asEClass
 	}
 
 	/**
@@ -189,7 +189,6 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 		useDomainElement = true
 	}
 
-
 	/**
 	 * Sets the candidates expression using a reference.
 	 * <p>
@@ -208,12 +207,12 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 			name = ref.name
 		}
 		if (it instanceof AbstractNodeMapping) {
-	        if (domainClass === null || domainClass.empty) {
-            	domainClass = SiriusDesigns.encode(ref.EType)
+	        if (domainClass === null || domainClass.blank) {
+            	domainClass = ref.EType as EClass
         	}
 		} else if (it instanceof EdgeMapping) {
-			if (domainClass === null || domainClass.empty) {
-				domainClass = SiriusDesigns.encode(ref.EType)
+			if (domainClass === null || domainClass.blank) {
+				domainClass = ref.EType as EClass
 			}
 		}
 	}
@@ -245,7 +244,8 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 			// when using a image in node, 
 			// we usually don't want icon on label
 			showIcon = false
-			(it as BorderedStyleDescription).borderSizeComputationExpression = "0" // hide border
+			// hide border
+			(it as BorderedStyleDescription).borderSizeComputationExpression = "0"
 		}
 
 		if (it instanceof BundledImageDescription) {
@@ -262,8 +262,8 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	 * @param it mapping to set
 	 * @param init initialization of the style
 	 */
-	def <T extends ContainerStyleDescription> 
-		style(ContainerMapping it, Class<T> type, (T)=>void init			
+	def <T extends ContainerStyleDescription> style(
+		ContainerMapping it, Class<T> type, (T)=>void init			
 	) {
         style = type.createStyle(init)
 	}
@@ -277,8 +277,8 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	 * @param it mapping to set
 	 * @param init initialization of the style
 	 */
-	def <T extends NodeStyleDescription> 
-		style(NodeMapping it, Class<T> type, (T)=>void init
+	def <T extends NodeStyleDescription> style(
+		NodeMapping it, Class<T> type, (T)=>void init
 	) {
         style = type.createStyle(init)
 	}
@@ -294,8 +294,9 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	 * @param condition of style application
 	 * @param init of created style (after default initialization)
 	 */
-	def <T extends ContainerStyleDescription> 
-		styleIf(ContainerMapping owner, Class<T> type, String condition, (T)=>void init
+	def <T extends ContainerStyleDescription> styleIf(
+			ContainerMapping owner, Class<T> type, 
+			String condition, (T)=>void init
 	) {
         // Init is required as default styling make not sense
         Objects.requireNonNull(init, "Conditional Style cannot have default properties")
@@ -319,8 +320,8 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	 * @param condition of style application
 	 * @param init of created style (after default initialization)
 	 */
-	def <T extends NodeStyleDescription> 
-		styleIf(NodeMapping owner, Class<T> type, String condition, (T)=>void init
+	def <T extends NodeStyleDescription> styleIf(
+		NodeMapping owner, Class<T> type, String condition, (T)=>void init
 	) {
 	    // Init is required as default styling make not sense
         Objects.requireNonNull(init, "Conditional Style cannot have default properties")
@@ -520,42 +521,48 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 	
 	/** Customizes a style reference with provided value. */
 	def customizeRef(
-		BasicLabelStyleDescription it, String condition, String styleReference, EObject value
+		BasicLabelStyleDescription it, String condition, 
+		String styleReference, EObject value
 	) {
 		customizeFeatures(condition, styleReference.styleRef(value))
 	}
 
 	/** Customizes a style attribute with provided expression. */
 	def void customize(
-		BasicLabelStyleDescription it, String condition, String styleAttribute, String expression
+		BasicLabelStyleDescription it, String condition, 
+		String styleAttribute, String expression
 	) {
 		customizeFeatures(condition, styleAttribute.styleAtt(expression))
 	}
 	
 	/** Customizes a style reference with provided value. */
 	def customize(
-		BasicLabelStyleDescription it, String condition, EReference styleReference, EObject value
+		BasicLabelStyleDescription it, String condition, 
+		EReference styleReference, EObject value
 	) {
 		customizeRef(condition, styleReference.name, value)
 	}
 
 	/** Customizes a style attribute with provided expression. */
 	def customize(
-		BasicLabelStyleDescription it, String condition, EAttribute styleAttribute, String expression
+		BasicLabelStyleDescription it, String condition, 
+		EAttribute styleAttribute, String expression
 	) {
 		customize(condition, styleAttribute.name, expression)
 	}
 
 	/** Customizes style properties. */
 	def void customizeFeatures(
-		BasicLabelStyleDescription it, String condition, EStructuralFeatureCustomization... featCustoms
+		BasicLabelStyleDescription it, String condition,
+		EStructuralFeatureCustomization... featCustoms
 	) {
 		doCustoms(condition, featCustoms)
 	}
 
 	/** Customizes a style reference with provided value. */
 	def customizeRef(
-		EdgeStyleDescription it, String condition, String styleReference, EObject value
+		EdgeStyleDescription it, String condition, 
+		String styleReference, EObject value
 	) {
 		customizeFeatures(condition, styleReference.styleRef(value))
 	}
@@ -583,7 +590,8 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
 
 	/** Customizes style properties. */
 	def void customizeFeatures(
-		EdgeStyleDescription it, String condition, EStructuralFeatureCustomization... featCustoms
+		EdgeStyleDescription it, String condition, 
+		EStructuralFeatureCustomization... featCustoms
 	) {
 		doCustoms(condition, featCustoms)
 	}
@@ -720,7 +728,9 @@ abstract class AbstractDiagramPart<T extends EObject> extends AbstractTypedEditi
     }
     
     /** Creates a delete description. */
-    protected def createElementDelete(String toolName, Enum<?> namespace, ModelOperation task) {
+    protected def createElementDelete(
+    	String toolName, Enum<?> namespace, ModelOperation task
+    ) {
         Objects.requireNonNull(task)
         // Alias is required as mapping declare drops
         DeleteElementDescription.createAs(namespace, toolName) [
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractEdition.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractEdition.xtend
index 5ffe8e6..1c08571 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractEdition.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractEdition.xtend
@@ -602,7 +602,7 @@ abstract class AbstractEdition extends AbstractIdentifiableElement {
 		labelSize = 10 // ODesign is provide 12, but eclipse default is Segoe:9
 		labelColor = SystemColor.extraRef("color:black")
 		
-		labelExpression = context.itemProviderLabel
+		labelExpression = itemProviderLabel
 	}
 	
 	/** Initializes variables of the tool. */
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractIdentifiableElement.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractIdentifiableElement.xtend
index 528a583..b0090ac 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractIdentifiableElement.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractIdentifiableElement.xtend
@@ -86,7 +86,6 @@ abstract class AbstractIdentifiableElement {
 		cat.name.id(path)
 	}
 	
-		
 	/**
 	 * Creates an identification with provided category.
 	 * <p>
@@ -181,7 +180,7 @@ abstract class AbstractIdentifiableElement {
 	 * @param path of element
 	 */
 	protected def String id(String category, String root, String path) {
-		context.createId(category, root, path)
+		category.createId(root, path)
 	}
 		
 	/**
@@ -250,7 +249,7 @@ abstract class AbstractIdentifiableElement {
 			Class<R> type, Class<? extends AbstractIdentifiableElement> container, 
 			Enum<?> cat, String name
 	) {
-		type.ref(context.getContentAlias(container), cat, name)
+		type.ref(container.contentAlias, cat, name)
 	}
 	
 	/**
@@ -267,7 +266,7 @@ abstract class AbstractIdentifiableElement {
 			Class<R> type, Class<? extends AbstractIdentifiableElement> container, 
 			Enum<?> cat, String name, (IdentifiedElement)=> R path
 	) {
-		type.ref(context.getContentAlias(container), cat, name, path)
+		type.ref(container.contentAlias, cat, name, path)
 	}
 	
 		
@@ -279,7 +278,7 @@ abstract class AbstractIdentifiableElement {
 	 * @param name of element
 	 */
 	protected def refId(Class<? extends AbstractIdentifiableElement> container, Enum<?> cat, String name) {
-		cat.id(context.getContentAlias(container), name)
+		cat.id(container.contentAlias, name)
 	}
 	
 	/**
@@ -355,7 +354,7 @@ abstract class AbstractIdentifiableElement {
 	 * @return aql expression
 	 */
 	def asAql(Class<? extends EObject> type) {
-		context.asEClass(type).asAql
+		type.asEClass().asAql
 	}
 	
 	/** Aql shortcut to evaluate a type. */
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractPropertySet.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractPropertySet.xtend
index 15bfcd2..7fa0ca9 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractPropertySet.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractPropertySet.xtend
@@ -42,6 +42,7 @@ import org.eclipse.sirius.viewpoint.FontFormat
 import org.eclipse.sirius.viewpoint.description.tool.ModelOperation
 
 import static extension org.mypsycho.modit.emf.sirius.api.SiriusDesigns.*
+import org.eclipse.emf.ecore.EClass
 
 /**
  * Adaptation of Sirius model into Java and EClass reflections API
@@ -87,15 +88,19 @@ abstract class AbstractPropertySet extends AbstractEdition {
 		this(parent, DEFAULT_NAME)
 	}
 	
-	def void setDomainClass(GroupDescription it, Class<? extends EObject> value) {
-		domainClass = value.asDomainClass
+	def void setDomainClass(GroupDescription it, Class<? extends EObject> type) {
+		domainClass = type.asEClass
+	}
+	
+	def void setDomainClass(GroupDescription it, EClass type) {
+		domainClass = SiriusDesigns.encode(type)
 	}
 	
 	/** Creates the content of Property Description. */
 	def ViewExtensionDescription createContent() {
 		ViewExtensionDescription.createAs(Ns.view.id(extensionName)) [
 			name = extensionName
-			metamodels += context.businessPackages
+			metamodels += businessPackages
 			initCategories
 		]
 	}
@@ -280,11 +285,6 @@ abstract class AbstractPropertySet extends AbstractEdition {
 	def createAction(String label, ModelOperation operation) {
 		label.createAction(null, operation)
 	}
-	
-	// ECore API has no constraint.
-	def String asDomainClass(Class<? extends EObject> type) {
-		context.asDomainClass(type)
-	}
 
 	def param(CustomDescription it, String key, String value) {
 		customExpressions += CustomExpression.create [
@@ -302,7 +302,7 @@ abstract class AbstractPropertySet extends AbstractEdition {
 	}
 	
 	def page(Category owner, String name, Class<? extends EObject> domain, (PageDescription)=>void init) {
-		owner.page(name, domain.asAql, init)
+		owner.page(name, domain.asDomainClass, init)
 	}
 
 	def groups(PageDescription owner, String... names) {
@@ -320,7 +320,7 @@ abstract class AbstractPropertySet extends AbstractEdition {
 	}
 	
 	def group(Category owner, String name, Class<? extends EObject> domain, (GroupDescription)=>void init) {
-		owner.group(name, domain.asAql, init)
+		owner.group(name, domain.asDomainClass, init)
 	}
 	
 	def noTitle(GroupDescription it) {
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTable.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTable.xtend
index 7273edc..d487bb0 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTable.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTable.xtend
@@ -80,10 +80,10 @@ abstract class AbstractTable<T extends TableDescription> extends AbstractTypedEd
 	 * 
 	 * @param parent of diagram
 	 */
-	new(Class<T> type, SiriusVpGroup parent, String dLabel, Class<? extends EObject> dClass) {
-		super(type, parent, dLabel)
+	new(Class<T> type, SiriusVpGroup parent, String label, Class<? extends EObject> domain) {
+		super(type, parent, label)
 		creationTasks.add [
-			domainClass = context.asDomainClass(dClass)
+			domainClass = domain.asDomainClass
 		]
 	}
 	
@@ -97,7 +97,7 @@ abstract class AbstractTable<T extends TableDescription> extends AbstractTypedEd
 	 * @param type of the description
 	 */
 	def void setDomainClass(LineMapping it, Class<? extends EObject> type) {
-		domainClass = context.asDomainClass(type)
+		domainClass = type.asEClass
 	}
 
     /**
@@ -305,7 +305,7 @@ abstract class AbstractTable<T extends TableDescription> extends AbstractTypedEd
      * @param action(root target, line target, line view)
      */
     def setDelete(LineMapping it, Procedure2<EObject, EObject> action) {
-        delete = context.expression(LINE_DELETE_ARGS.params, action).toOperation
+        delete = LINE_DELETE_ARGS.params.expression(action).toOperation
     }
 	
     /**
@@ -400,7 +400,7 @@ abstract class AbstractTable<T extends TableDescription> extends AbstractTypedEd
     def createLine(String line, String role, String toolLabel, 
     	Procedure3<EObject, EObject, EObject> action
 	) {
-		line.createLine(toolLabel, role, context.expression(CREATE_LINE_PARAMS, action).toOperation)
+		line.createLine(toolLabel, role, CREATE_LINE_PARAMS.expression(action).toOperation)
 	}
 	
     /**
@@ -434,7 +434,7 @@ abstract class AbstractTable<T extends TableDescription> extends AbstractTypedEd
     def createAddLine(TableDescription owner, String line, String role, String toolLabel, 
     	Procedure3<EObject, EObject, EObject> action
 	) {
-		val op = context.expression(CREATE_LINE_PARAMS, action).toOperation
+		val op = CREATE_LINE_PARAMS.expression(action).toOperation
 		line.createLine(toolLabel, role, op) => [
 			owner.ownedCreateLine += it
 		]
@@ -471,7 +471,7 @@ abstract class AbstractTable<T extends TableDescription> extends AbstractTypedEd
     def createAddLine(LineMapping owner, String line, String role, String toolLabel, 
     	Procedure3<EObject, EObject, EObject> action
 	) {
-		val op = context.expression(CREATE_LINE_PARAMS, action).toOperation
+		val op = CREATE_LINE_PARAMS.expression(action).toOperation
 		line.createLine(toolLabel, role, op) => [
 			owner.create += it
 		]
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTypedEdition.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTypedEdition.xtend
index ca59419..9cfa2f0 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTypedEdition.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/AbstractTypedEdition.xtend
@@ -44,10 +44,10 @@ abstract class AbstractTypedEdition<T extends EObject> extends AbstractEdition {
 		creationTasks.add [ // xtend fails to infere '+=' .
 			if (it instanceof RepresentationExtensionDescription) {
 				name = contentAlias
-				metamodel += context.businessPackages
+				metamodel += businessPackages
 			} else if (it instanceof RepresentationDescription) {
 				name = contentAlias
-				metamodel += context.businessPackages
+				metamodel += businessPackages
 			}
 		]
 	}
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/DefaultPropertiesExtension.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/DefaultPropertiesExtension.xtend
index 65b9049..0c00f14 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/DefaultPropertiesExtension.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/DefaultPropertiesExtension.xtend
@@ -165,7 +165,7 @@ class DefaultPropertiesExtension extends AbstractPropertySet {
 	
 	/** Requires overriding for static page. */
 	def getDateExpression(String iValue, String iFeat) {
-		context.expression(params(iValue, iFeat)) [
+		params(iValue, iFeat).expression [
 			EObject it, EStructuralFeature feat |
 			val result = eGet(feat) as Date
 			result === null
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusCrossTable.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusCrossTable.xtend
index 7c3da34..28d9217 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusCrossTable.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusCrossTable.xtend
@@ -68,7 +68,7 @@ abstract class SiriusCrossTable extends AbstractTable<CrossTableDescription> {
 	 * @param type of the description
 	 */
 	def void setDomainClass(ElementColumnMapping it, Class<? extends EObject> type) {
-		domainClass = context.asDomainClass(type)
+		domainClass = type.asEClass
 	}
 		   
     /**
@@ -94,7 +94,7 @@ abstract class SiriusCrossTable extends AbstractTable<CrossTableDescription> {
 	 * @param type of the description
 	 */
 	def void setDomainClass(IntersectionMapping it, Class<? extends EObject> type) {
-		domainClass = context.asDomainClass(type)
+		domainClass = type.asEClass
 	}
 		   
     /**
@@ -185,7 +185,7 @@ abstract class SiriusCrossTable extends AbstractTable<CrossTableDescription> {
 	) {
         Objects.requireNonNull(initializer)
         name.column[
-        	domainClass = domain.asDomainClass
+        	domainClass = domain
         	initializer.apply(it)
         ]
     }
@@ -349,7 +349,7 @@ abstract class SiriusCrossTable extends AbstractTable<CrossTableDescription> {
 		Class<? extends EObject> domain, 
 		String candidatesExpr, (IntersectionMapping)=>void descr
 	) {
-		owner.cells(mappingName, context.asDomainClass(domain), candidatesExpr, descr)
+		owner.cells(mappingName, domain.asDomainClass, candidatesExpr, descr)
 	}
 
 	/** Defines the lines of Element-based cell. */
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDesigns.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDesigns.xtend
index f7ebd6e..44fcb9f 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDesigns.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDesigns.xtend
@@ -92,7 +92,7 @@ class SiriusDesigns {
 	 * @return associated text
 	 */
 	static def String encode(EClassifier it) {
-		'''«EPackage.name»::«name»'''
+		asAql
 	}
 	
 	   
@@ -250,7 +250,7 @@ class SiriusDesigns {
 		false
 	}
 	
-	/** Aql request to views target */
+	/** Aql request to evaluate if selected target all matches a type. */
 	static def final allTargetViews(EClassifier eclass) {
 		// Usefull for OperationAction
 		'''
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDiagramExtension.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDiagramExtension.xtend
index b5e6ad9..f20a1b8 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDiagramExtension.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusDiagramExtension.xtend
@@ -73,8 +73,8 @@ abstract class SiriusDiagramExtension extends AbstractDiagramPart<DiagramExtensi
 	}
 	
 	def getVpUri(RepresentationDescription it) {
-		eContainer(Group) == context.getContent() // local representation
-			? context.pluginId.encodeVpUri(eContainer(Viewpoint).name)
+		eContainer(Group) == context.content // local representation
+			? pluginId.encodeVpUri(eContainer(Viewpoint).name)
 			: extraVpUri
 	}
 
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusFeatureTable.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusFeatureTable.xtend
index 30c0df3..1ca2ca5 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusFeatureTable.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusFeatureTable.xtend
@@ -174,7 +174,8 @@ abstract class SiriusFeatureTable extends AbstractTable<EditionTableDescription>
 	protected def void setDirectEdit(FeatureColumnMapping it, 
 		Procedure2<? extends EObject, String> operation
 	) {
-		directEdit = context.expression(params(EditArg.lineSemantic, SiriusDesigns.EDIT_VALUE), operation)
+		directEdit = #[ EditArg.lineSemantic, SiriusDesigns.EDIT_VALUE ]
+			.params.expression(operation)
 	}
 	
 }
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusTree.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusTree.xtend
index e389fc1..737d784 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusTree.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusTree.xtend
@@ -61,11 +61,11 @@ abstract class SiriusTree extends AbstractTypedEdition<TreeDescription> {
 	 * @param descrLabel displayed on representation groups
 	 * @param domain class of diagram
 	 */
-	new(SiriusVpGroup parent, String descrLabel, Class<? extends EObject> domain) {
-		super(TreeDescription, parent, descrLabel)
+	new(SiriusVpGroup parent, String label, Class<? extends EObject> domain) {
+		super(TreeDescription, parent, label)
 		this.domain = domain
 		creationTasks.add[
-			domainClass = context.asDomainClass(domain)
+			domainClass = domain.asDomainClass
 		]
 	}
 		
@@ -98,10 +98,35 @@ abstract class SiriusTree extends AbstractTypedEdition<TreeDescription> {
 	 * @param type of the description
 	 */
 	def void setDomainClass(TreeItemMapping it, Class<? extends EObject> type) {
-		domainClass = context.asDomainClass(type)
+		domainClass = type.asEClass
 	}
 	
-	   
+	/**
+	 * Sets the domain class of a description.
+	 * <p>
+	 * EClass is resolved using businessPackages of AbstractGroup.
+	 * </p>
+	 * 
+	 * @param it description to define
+	 * @param type of the description
+	 */
+	def void setDomainClass(TreeItemMapping it, EClass type) {
+		domainClass = SiriusDesigns.encode(type)
+	}
+		   
+    /**
+     * Sets the domain class of a description.
+     * <p>
+     * EClass is resolved using businessPackages of AbstractGroup.
+     * </p>
+     * 
+     * @param it description to define
+     * @param type of the description
+     */
+    def void setDomainClass(TreeDescription it, Class<? extends EObject> type) {
+        domainClass = type.asEClass
+    }
+	
     /**
      * Sets the domain class of a description.
      * <p>
diff --git a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusVpGroup.xtend b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusVpGroup.xtend
index c01c041..23eef8b 100644
--- a/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusVpGroup.xtend
+++ b/plugins/modit.sirius/src/org/mypsycho/modit/emf/sirius/api/SiriusVpGroup.xtend
@@ -33,6 +33,7 @@ import org.eclipse.sirius.viewpoint.description.UserColorsPalette
 import org.eclipse.sirius.viewpoint.description.UserFixedColor
 import org.eclipse.sirius.viewpoint.description.Viewpoint
 import org.mypsycho.modit.emf.sirius.SiriusModelProvider
+import org.eclipse.emf.ecore.EClass
 
 /**
  * Class regrouping a common adaptation of Sirius into Java and EClass reflection for group.
@@ -110,7 +111,20 @@ abstract class SiriusVpGroup extends SiriusModelProvider {
 	 * @param type to encode
 	 * @return encoded typee
 	 */
-	def EClassifier asEClass(Class<? extends EObject> type) {
+	def EClass asEClass(Class<? extends EObject> it) {
+		it?.asEClassifier as EClass
+	}
+	
+	/**
+	 * Provides text used for domainClass properties from java Class.
+	 * 
+	 * @param type to encode
+	 * @return encoded typee
+	 */
+	def EClassifier asEClassifier(Class<?> type) {
+		if (type === null) {
+			return null
+		}
 		val result = (businessPackages + BUILT_IN_PACKAGES)
 			.flatMap[ EClassifiers ]
 			.findFirst[ instanceClass == type ]
@@ -118,11 +132,10 @@ abstract class SiriusVpGroup extends SiriusModelProvider {
 		if (result === null) {
 			val names = (businessPackages + BUILT_IN_PACKAGES)
 				.join(',')[ name ]
-			'''EClass of «type» is not defined in packages [«names»]'''.verify(false)
+			'''EClassifier of «type.name» is not defined in packages [«names»]'''.verify(false)
 		}
 		result
 	}
-	
 
 	//
 	// Identification
@@ -139,15 +152,14 @@ abstract class SiriusVpGroup extends SiriusModelProvider {
 	 * @param context to identify
 	 * @return identification 
 	 */
-	def getContentAlias(Class<?> context) {
-		if (!context.anonymousClass) {
-			return context.simpleName
+	def getContentAlias(Class<?> it) {
+		if (!anonymousClass) {
+			return simpleName
 		}
 
-		var fullname = context.name
-		fullname.substring(
-			fullname.lastIndexOf(".") + 1, 
-			fullname.lastIndexOf("$")
+		name.substring(
+			name.lastIndexOf(".") + 1, 
+			name.lastIndexOf("$")
 		)
 	}