diff --git a/src/org/ntlab/deltaViewer/CollaborationViewer.java b/src/org/ntlab/deltaViewer/CollaborationViewer.java
index 1db4730..19f68a0 100644
--- a/src/org/ntlab/deltaViewer/CollaborationViewer.java
+++ b/src/org/ntlab/deltaViewer/CollaborationViewer.java
@@ -185,7 +185,16 @@
 				tgtObjId = calledMethodExec.getArguments().get(0).getId();
 				ObjectVertex tgtObjectVertex = objectToVertexMap.get(tgtObjId);
 
-				createObjectRefrence(srcClassName, srcObjId, tgtObjId);
+				if (!methodExecToVertexMap.containsKey(calledMethodExec)) {
+					createMethodExecutionVertex(calledMethodExec.getThisObjId(), methodInvStatement.getCallerSideMethodName(), calledMethodExec);
+					update();
+					moveArgumentObjectVertex(calledMethodExec, tgtObjectVertex, methodExecToVertexMap.get(calledMethodExec));
+					update();
+					createObjectRefrence(srcClassName, srcObjId, tgtObjId);
+					removeCalledMethodExecutionVertex(null, prevMethodExec, calledMethodExec);
+				} else {
+					createObjectRefrence(srcClassName, srcObjId, tgtObjId);
+				}
 				if (methodExecToVertexMap.containsKey(prevMethodExec)) {
 					if (methodExecToVertexMap.get(prevMethodExec).getLocals().contains(tgtObjectVertex)) {
 						methodExecToVertexMap.get(prevMethodExec).getLocals().remove(tgtObjectVertex);
diff --git a/src/org/ntlab/deltaViewer/MagnetRONViewer.java b/src/org/ntlab/deltaViewer/MagnetRONViewer.java
index f6744b1..287aefa 100644
--- a/src/org/ntlab/deltaViewer/MagnetRONViewer.java
+++ b/src/org/ntlab/deltaViewer/MagnetRONViewer.java
@@ -214,7 +214,8 @@
 		Point absPtSrcCell = getAbsolutePointforCell(sourceCell);
 		mxgraph.getModel().beginUpdate();
 		try {
-			Object vertex = mxgraph.insertDeltaVertex(mxDefaultParent, objectVertex.getLabel(), objectVertex.getLabel(), absPtSrcCell.getX() + overlapWidth, absPtSrcCell.getY() + overlapHeight, VERTEX_OBJECT_SIZE.getWidth(), VERTEX_OBJECT_SIZE.getHeight(), "fillColor=white"); //creates a white vertex. 		
+			Object vertex = mxgraph.insertDeltaVertex(mxDefaultParent, alias.getObjectId(), objectVertex.getLabel(), absPtSrcCell.getX() + overlapWidth, absPtSrcCell.getY() + overlapHeight, VERTEX_OBJECT_SIZE.getWidth(), VERTEX_OBJECT_SIZE.getHeight(), "fillColor=white"); //creates a white vertex. 		
+//			Object vertex = mxgraph.insertDeltaVertex(mxDefaultParent, objectVertex.getLabel(), objectVertex.getLabel(), absPtSrcCell.getX() + overlapWidth, absPtSrcCell.getY() + overlapHeight, VERTEX_OBJECT_SIZE.getWidth(), VERTEX_OBJECT_SIZE.getHeight(), "fillColor=white"); //creates a white vertex. 		
 			objectVertex.setCell(vertex);
 			Object edge = mxgraph.insertDeltaEdge(mxDefaultParent, fieldName, null, sourceCell, vertex);
 			setEdgePoint((mxCell)edge, absPtSrcCell, objectVertex.getInitialPoint());
@@ -450,7 +451,7 @@
 	 * @param sourceVertexObject move
 	 * @param targetVertexMethodExec
 	 */
-	private void moveArgumentObjectVertex(MethodExecution methodExec, ObjectVertex sourceVertexObject, MethodExecutionVertex targetVertexMethodExec) {
+	protected void moveArgumentObjectVertex(MethodExecution methodExec, ObjectVertex sourceVertexObject, MethodExecutionVertex targetVertexMethodExec) {
 		mxICell sourceCell = (mxICell)sourceVertexObject.getCell();
 		mxICell targetCell = (mxICell) targetVertexMethodExec.getCell();
 		//		mxICell parentTargetMethodExecCell = targetMethodExecCell.getParent();
@@ -740,6 +741,7 @@
 			}
 
 			Object vertex = mxgraph.insertDeltaVertex(object, methodSignature, methodSignature, "fillColor=white"); //creates a white vertex. 
+			mxgraph.orderCells(false, new Object[] {vertex});
 			System.out.println("makeVertexMethodExecution: " + ((mxICell)vertex).getId() + " in " + objId + " (" + standardX + ", " + yCor * (time + 1) + standardY + ")");
 
 			MethodExecutionVertex vertexMethodExecution =  new MethodExecutionVertex(methodSignature, vertex, standardX , yCor * (time + 1) + standardY, VERTEX_METHOD_EXECUTION_SIZE.getWidth(), VERTEX_METHOD_EXECUTION_SIZE.getHeight());