diff --git a/src/org/ntlab/animations/MagnetRONAnimation.java b/src/org/ntlab/animations/MagnetRONAnimation.java
index 151fea1..42379dd 100644
--- a/src/org/ntlab/animations/MagnetRONAnimation.java
+++ b/src/org/ntlab/animations/MagnetRONAnimation.java
@@ -179,6 +179,8 @@
 		STOPPED
 	}
 
+//	private static int animationCount = 0;
+	
 	/**
 	 * The constructor of {@code MagnetRONAnimation}.
 	 * 
@@ -362,12 +364,16 @@
 								updateCurrentCycle(getCurrentCycleCount());
 								jumpTo(getCurrentCycleCount());
 							} else if(Math.abs(getCurrentCycleCount()) >= Math.abs(getTotalCycleCount())){
+//								animationCount = 0;
+//								System.out.println(TAG + ": animationCount=" + animationCount);
 								onFinished();
 							}
 						}
 					}, getInitialDelay(), getDelay(), TimeUnit.MILLISECONDS);
 					setScheduledFuture(scheduledFuture);
 					setCurrentStatus(Status.RUNNING);
+//					animationCount = 1;
+//					System.out.println(TAG + ": animationCount=" + animationCount);
 				};
 				break;
 			case PAUSED:
@@ -382,6 +388,22 @@
 		};
 	}
 	
+//	public static void waitAnimationEnd() {
+//		while (animationCount > 0) {
+//			try {
+//				Thread.sleep(1L);
+//			} catch (InterruptedException e) {
+//				e.printStackTrace();
+//			}
+//		}
+//		// Buffer for another waiting animation. 
+//		try {
+//			Thread.sleep(30L);
+//		} catch (InterruptedException e) {
+//			e.printStackTrace();
+//		}
+//	}
+	
 	public void syncPlay() {
 		if (getCurrentStatus() == Status.STOPPED) {
 			try {
diff --git a/src/org/ntlab/deltaViewer/CollaborationViewer.java b/src/org/ntlab/deltaViewer/CollaborationViewer.java
index 633639d..282704a 100644
--- a/src/org/ntlab/deltaViewer/CollaborationViewer.java
+++ b/src/org/ntlab/deltaViewer/CollaborationViewer.java
@@ -118,12 +118,12 @@
 				System.out.println("ERROR : Not exist alias.");
 			}
 //		} else {
-			// TODO Considering fast-forwarding animations. 			
+			// TODO: Considering fast-forwarding animations. 			
 //		}
 	}
 
 	private void doLastAnimation(int numFrame, TracePoint relatedPoint) {
-		// TODO Implement doLastAnimation to support plural Delta.
+		// TODO: Implement doLastAnimation to support plural Delta.
 		outputLog();
 		curFrame = numFrame;
 		List<Alias> aliasList = aliasCollector.getAliasList();
@@ -170,8 +170,8 @@
 			String tgtObjId = null;
 
 			//Array��List�̂Ƃ��������x����t����i�m���ɕ������Ă�����̂Ƃ�)getSignature->contains("List.get(") || "Map.get(") <�z���C�g���X�g>
-//				if (methodExec.getSignature().contains("List.add(") ||
-//						methodExec.getSignature().contains("Map.put(")) {
+//			if (methodExec.getSignature().contains("List.add(") ||
+//					methodExec.getSignature().contains("Map.put(")) {
 			if (calledMethodExec.isCollectionType()
 					&& (methodSignature.contains("add(") 
 							|| methodSignature.contains("set(") 
@@ -260,104 +260,117 @@
 //			updateObjectVertices();
 //		}
 
-		// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.
-		mxgraph.getModel().beginUpdate();
-		try {
-			List<MethodExecution> meList = new ArrayList<>(methodExecToVertexMap.keySet());
-			Collections.reverse(meList);
-			System.out.println(meList.size());
-			for(int i = 0; i < meList.size(); i++) {
-				String objectId = meList.get(i).getThisObjId();
-				ObjectVertex sourceVertexObject = objectToVertexMap.get(objectId); // sourceVertex
-				MethodExecution me = meList.get(i);
-				if (nextAlias != null && me.getSignature().equals(nextAlias.getMethodSignature())) break;
-				if (i != meList.size()-1) {
-					for(Statement st: me.getStatements()) {
-						if(st instanceof MethodInvocation) {
-							MethodExecution calledMethodExec = ((MethodInvocation) st).getCalledMethodExecution();
-							String calledObjectId = calledMethodExec.getThisObjId();
-							System.out.println(calledObjectId);
-							if(objectToVertexMap.containsKey(calledObjectId)) {
-								mxICell calledCell = (mxICell)objectToVertexMap.get(calledObjectId).getCell();
-								Point2D absolutePointCalledCell = getAbsolutePointforCell(calledCell);
-								System.out.println(objectId + ", " + me.getSignature());
-//								objectToVertexMap.get(calledObjectId).resetCellPosition();
-//								if (methodExecToVertexMap.get(methodExec).getArguments().contains(objectToVertexMap.get(calledObjectId)) || methodExecToVertexMap.get(methodExec).getLocals().contains(objectToVertexMap.get(calledObjectId))) {
-//									calledCell.getParent().remove(calledCell);
-//									calledCell.setParent(mxDefaultParent);
-//									calledCell.getGeometry().setX(absolutePointCalledCell.getX());
-//									calledCell.getGeometry().setY(absolutePointCalledCell.getY());
-//									deltaAnimation.setVertexAnimation(calledCell, new mxPoint(objectToVertexMap.get(calledObjectId).getInitialX(), objectToVertexMap.get(calledObjectId).getInitialY()));
-//									deltaAnimation.startVertexAnimation();
-//								}
-								removeCalledMethodExecutionVertex(sourceVertexObject, me.getCallerMethodExecution(), me);
-								updateObjectVertices();
-//					    		removeVertexMethodExecution(sourceVertexObject, methodExec);
-//			    				update();
-								break;
-							}
+		List<MethodExecution> meList = new ArrayList<>(methodExecToVertexMap.keySet());
+		Collections.reverse(meList);
+		System.out.println(meList.size());
+		for(int i = 0; i < meList.size(); i++) {
+			String objectId = meList.get(i).getThisObjId();
+			ObjectVertex sourceVertexObject = objectToVertexMap.get(objectId); // sourceVertex
+			MethodExecution me = meList.get(i);
+			if (nextAlias != null && me.getSignature().equals(nextAlias.getMethodSignature())) break;
+			if (i != meList.size()-1) {
+				for(Statement st: me.getStatements()) {
+					if(st instanceof MethodInvocation) {
+						MethodExecution calledMethodExec = ((MethodInvocation) st).getCalledMethodExecution();
+						String calledObjectId = calledMethodExec.getThisObjId();
+						System.out.println(calledObjectId);
+						if(objectToVertexMap.containsKey(calledObjectId)) {
+							mxICell calledCell = (mxICell)objectToVertexMap.get(calledObjectId).getCell();
+							Point2D absolutePointCalledCell = getAbsolutePointforCell(calledCell);
+							System.out.println(objectId + ", " + me.getSignature());
+//							objectToVertexMap.get(calledObjectId).resetCellPosition();
+//							if (methodExecToVertexMap.get(methodExec).getArguments().contains(objectToVertexMap.get(calledObjectId)) || methodExecToVertexMap.get(methodExec).getLocals().contains(objectToVertexMap.get(calledObjectId))) {
+//								calledCell.getParent().remove(calledCell);
+//								calledCell.setParent(mxDefaultParent);
+//								calledCell.getGeometry().setX(absolutePointCalledCell.getX());
+//								calledCell.getGeometry().setY(absolutePointCalledCell.getY());
+//								deltaAnimation.setVertexAnimation(calledCell, new mxPoint(objectToVertexMap.get(calledObjectId).getInitialX(), objectToVertexMap.get(calledObjectId).getInitialY()));
+//								deltaAnimation.startVertexAnimation();
+//							}
+							removeCalledMethodExecutionVertex(sourceVertexObject, me.getCallerMethodExecution(), me);
+							updateObjectVertices();
+//				    		removeVertexMethodExecution(sourceVertexObject, methodExec);
+//		    				update();
+							break;
 						}
 					}
-				}  else {
-					outputLog();
-
-					// Change!
-					List<ObjectVertex> arguments = new ArrayList<>(methodExecToVertexMap.get(me).getArguments());
-					List<ObjectVertex> locals = new ArrayList<>(methodExecToVertexMap.get(me).getLocals());
-					if (arguments.size() != 0) {
-						for (ObjectVertex vo: arguments) {
-							mxICell cell = (mxICell)vo.getCell();
-							Point2D absolutePointCell = getAbsolutePointforCell(cell);
-//							cell.getParent().remove(cell);
-//							cell.setParent(mxDefaultParent);
-							if (!cell.getParent().equals(getMxDefaultParent())) {
-								// If parent of ObjectVertex cell isn't mxDefaltParent, reset parent.
-								cell.getParent().remove(cell);
-								cell.setParent(getMxDefaultParent());
-							}
-							cell.getGeometry().setX(absolutePointCell.getX());
-							cell.getGeometry().setY(absolutePointCell.getY());
-//							deltaAnimation.setVertexAnimation(cell, new mxPoint(vo.getInitialX(), vo.getInitialY()));
-//							deltaAnimation.startVertexAnimation();
-//							deltaAnimation.sleepThread(DEFAULT_THREAD_SLEEP_MILLIS);
-							MagnetRONAnimation vertexAnim = new TranslateAnimation(mxgraph, getGraphComponent());
-							vertexAnim.setTotalCycleCount(10);
-							vertexAnim.setDelay(100);
-							vertexAnim.init(cell, vo.getInitialX(), vo.getInitialY(), threadPoolExecutor);
-							vertexAnim.play();
-							sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
-							methodExecToVertexMap.get(me).getArguments().remove(vo);
-						}
-					}else if (locals.size() != 0) {
-						for (ObjectVertex vo: locals) {
-							mxICell cell = (mxICell)vo.getCell();
-							Point2D absolutePointCell = getAbsolutePointforCell(cell);
-//							cell.getParent().remove(cell);
-//							cell.setParent(mxDefaultParent);
-							if (!cell.getParent().equals(getMxDefaultParent())) {
-								// If parent of ObjectVertex cell isn't mxDefaltParent, reset parent.
-								cell.getParent().remove(cell);
-								cell.setParent(getMxDefaultParent());
-							}
-							cell.getGeometry().setX(absolutePointCell.getX());
-							cell.getGeometry().setY(absolutePointCell.getY());
-//							deltaAnimation.setVertexAnimation(cell, new mxPoint(vo.getInitialX(), vo.getInitialY()));
-//							deltaAnimation.startVertexAnimation();
-//							deltaAnimation.sleepThread(DEFAULT_THREAD_SLEEP_MILLIS);
-							MagnetRONAnimation vertexAnim = new TranslateAnimation(mxgraph, getGraphComponent());
-							vertexAnim.setTotalCycleCount(10);
-							vertexAnim.setDelay(100);
-							vertexAnim.init(cell, vo.getInitialX(), vo.getInitialY(), threadPoolExecutor);
-							vertexAnim.play();
-							sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
-							methodExecToVertexMap.get(me).getLocals().remove(vo);
-						}
-					}
-					updateObjectVertices();	    			
 				}
+			}  else {
+				outputLog();
+
+				// Change!
+				List<ObjectVertex> arguments = new ArrayList<>(methodExecToVertexMap.get(me).getArguments());
+				List<ObjectVertex> locals = new ArrayList<>(methodExecToVertexMap.get(me).getLocals());
+				if (arguments.size() != 0) {
+					for (ObjectVertex vo: arguments) {
+						mxICell cell = (mxICell)vo.getCell();
+						Point2D absolutePointCell = getAbsolutePointforCell(cell);
+						// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.
+						mxgraph.getModel().beginUpdate();
+						synchronized (mxgraph.getModel()) {
+							try {
+//								cell.getParent().remove(cell);
+//								cell.setParent(mxDefaultParent);
+								if (!cell.getParent().equals(getMxDefaultParent())) {
+									// If parent of ObjectVertex cell isn't mxDefaltParent, reset parent.
+									cell.getParent().remove(cell);
+									cell.setParent(getMxDefaultParent());
+								}
+								cell.getGeometry().setX(absolutePointCell.getX());
+								cell.getGeometry().setY(absolutePointCell.getY());
+							} finally {
+								mxgraph.getModel().endUpdate();
+							}
+						}
+
+//						deltaAnimation.setVertexAnimation(cell, new mxPoint(vo.getInitialX(), vo.getInitialY()));
+//						deltaAnimation.startVertexAnimation();
+//						deltaAnimation.sleepThread(DEFAULT_THREAD_SLEEP_MILLIS);
+						MagnetRONAnimation vertexAnim = new TranslateAnimation(mxgraph, getGraphComponent());
+						vertexAnim.setTotalCycleCount(10);
+						vertexAnim.setDelay(100);
+						vertexAnim.init(cell, vo.getInitialX(), vo.getInitialY(), threadPoolExecutor);
+//						vertexAnim.play();
+//						sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+						vertexAnim.syncPlay();
+						methodExecToVertexMap.get(me).getArguments().remove(vo);
+					}
+				}else if (locals.size() != 0) {
+					for (ObjectVertex vo: locals) {
+						mxICell cell = (mxICell)vo.getCell();
+						Point2D absolutePointCell = getAbsolutePointforCell(cell);
+						// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.
+						mxgraph.getModel().beginUpdate();
+						synchronized (mxgraph.getModel()) {
+							try {
+//								cell.getParent().remove(cell);
+//								cell.setParent(mxDefaultParent);
+								if (!cell.getParent().equals(getMxDefaultParent())) {
+									// If parent of ObjectVertex cell isn't mxDefaltParent, reset parent.
+									cell.getParent().remove(cell);
+									cell.setParent(getMxDefaultParent());
+								}
+								cell.getGeometry().setX(absolutePointCell.getX());
+								cell.getGeometry().setY(absolutePointCell.getY());
+							} finally {
+								mxgraph.getModel().endUpdate();
+							}
+						}
+//						deltaAnimation.setVertexAnimation(cell, new mxPoint(vo.getInitialX(), vo.getInitialY()));
+//						deltaAnimation.startVertexAnimation();
+//						deltaAnimation.sleepThread(DEFAULT_THREAD_SLEEP_MILLIS);
+						MagnetRONAnimation vertexAnim = new TranslateAnimation(mxgraph, getGraphComponent());
+						vertexAnim.setTotalCycleCount(10);
+						vertexAnim.setDelay(100);
+						vertexAnim.init(cell, vo.getInitialX(), vo.getInitialY(), threadPoolExecutor);
+//						vertexAnim.play();
+//						sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+						vertexAnim.syncPlay();
+						methodExecToVertexMap.get(me).getLocals().remove(vo);
+					}
+				}
+				updateObjectVertices();	    			
 			}
-		} finally {
-			mxgraph.getModel().endUpdate();
 		}
 		update();
 	}
diff --git a/src/org/ntlab/deltaViewer/MagnetRONViewer.java b/src/org/ntlab/deltaViewer/MagnetRONViewer.java
index 27d31cd..a30c423 100644
--- a/src/org/ntlab/deltaViewer/MagnetRONViewer.java
+++ b/src/org/ntlab/deltaViewer/MagnetRONViewer.java
@@ -66,7 +66,8 @@
 	protected static Dimension DEFAULT_OBJECT_VERTEX_SIZE = new Dimension(70, 70);
 	protected static Dimension DEFAULT_METHOD_EXECUTION_VERTEX_SIZE = new Dimension(55, 20);
 
-	protected static long DEFAULT_THREAD_SLEEP_MILLIS = 1100;
+	protected static long DEFAULT_THREAD_SLEEP_MILLIS = 1100L;
+	protected static long POSTPONE_ANIMATION_MILLIS = 400L;
 
 	protected IAliasCollector aliasCollector;
 
@@ -176,6 +177,7 @@
 				createObjectVertexOnConstractor(alias);
 				createMethodExecutionVertex(alias.getObjectId(), ((MethodInvocation)alias.getOccurrencePoint().getStatement()).getCallerSideMethodName(), ((MethodInvocation)alias.getOccurrencePoint().getStatement()).getCalledMethodExecution());
 				update();
+//				sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
 				removeMethodExecutionVertex(alias);
 				update();
 				break;
@@ -338,8 +340,8 @@
 		mxgraph.getModel().beginUpdate();
 		synchronized (mxgraph.getModel()) {
 			try {
-				//			dstCell.getParent().remove(dstCell);
-				//			dstCell.setParent(mxDefaultParent);
+//				dstCell.getParent().remove(dstCell);
+//				dstCell.setParent(mxDefaultParent);
 				if (!dstCell.getParent().equals(getMxDefaultParent())) {
 					// If parent of ObjectVertex cell isn't mxDefaltParent, reset parent.
 					dstCell.getParent().remove(dstCell);
@@ -393,8 +395,8 @@
 		mxgraph.getModel().beginUpdate();
 		synchronized (mxgraph.getModel()) {
 			try {
-				//			dstCell.getParent().remove(dstCell);
-				//			dstCell.setParent(mxDefaultParent);
+//				dstCell.getParent().remove(dstCell);
+//				dstCell.setParent(mxDefaultParent);
 				if (!dstCell.getParent().equals(getMxDefaultParent())) {
 					// If parent of ObjectVertex cell isn't mxDefaltParent, reset parent.
 					dstCell.getParent().remove(dstCell);
@@ -531,11 +533,11 @@
 				}
 
 				mxgraph.orderCells(true, new Object[] {srcCell});
-				//			srcCell.setParent(dstCell.getParent());
-				//			dstCell.getParent().insert(srcCell);
+//				srcCell.setParent(dstCell.getParent());
+//				dstCell.getParent().insert(srcCell);
 				if (srcCell.getParent() == null || !srcCell.getParent().equals(dstCell.getParent())) {
 					// TODO: Confirm why not need following comment out.
-					//				if (srcCell.getParent() != null) srcCell.getParent().remove(srcCell);
+//					if (srcCell.getParent() != null) srcCell.getParent().remove(srcCell);
 					srcCell.setParent(dstCell.getParent());
 					dstCell.getParent().insert(srcCell);
 				}
@@ -563,17 +565,18 @@
 		vertexAnim.init(srcCell, 
 				dstCell.getGeometry().getX() - (srcCellWidth / Math.sqrt(2.5)) + (srcCellWidth * time), dstCell.getGeometry().getY() + dstCellHeight, 
 				threadPoolExecutor);
-		//			vertexAnim.play();
-		//			sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//		vertexAnim.play();
+//		sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
 		vertexAnim.syncPlay();
 		
 		// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.   	
 		mxgraph.getModel().beginUpdate();
 		synchronized (mxgraph.getModel()) {
 			try {
-				//			srcCell.setParent(dstCell.getParent());
-				//			dstCell.getParent().insert(srcCell);
+//				srcCell.setParent(dstCell.getParent());
+//				dstCell.getParent().insert(srcCell);
 				if (!srcCell.getParent().equals(dstCell.getParent())) {
+					// TODO: Confirm why not need following comment out.
 					srcCell.getParent().remove(srcCell);
 					srcCell.setParent(dstCell.getParent());
 					dstCell.getParent().insert(srcCell);
@@ -639,11 +642,11 @@
 			synchronized (mxgraph.getModel()) {
 				try {
 					mxgraph.orderCells(true, new Object[] {srcCell});
-					//				srcCell.setParent(dstCell.getParent());
-					//				dstCell.getParent().insert(srcCell);
+//					srcCell.setParent(dstCell.getParent());
+//					dstCell.getParent().insert(srcCell);
 					if (srcCell.getParent() == null || !srcCell.getParent().equals(dstCell.getParent())) {
 						// TODO: Confirm why not need following comment out.
-						//					if (srcCell.getParent() != null) srcCell.getParent().remove(srcCell);
+//						if (srcCell.getParent() != null) srcCell.getParent().remove(srcCell);
 						srcCell.setParent(dstCell.getParent());
 						dstCell.getParent().insert(srcCell);
 					}
@@ -669,8 +672,9 @@
 			vertexAnim.init(srcCell, 
 					dstCell.getGeometry().getX() - overlapWidth, dstCell.getGeometry().getY()  - overlapHeight + (srcCellHeight * time), 
 					threadPoolExecutor);
-//					vertexAnim.play();
-//					sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//			vertexAnim.play();
+//			sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//			sleepMainThread(POSTPONE_ANIMATION_MILLIS);
 			vertexAnim.syncPlay();
 
 			// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.
@@ -699,16 +703,21 @@
 			mxgraph.getModel().beginUpdate();
 			synchronized (mxgraph.getModel()) {
 				try {
-					//				srcCell.remove(dstCell.getParent());
-					//				dstCell.getParent().setParent(mxDefaultParent);
-					//				srcCell.setParent(dstCell.getParent());
-					//				dstCell.getParent().insert(srcCell);
-					if (!dstCell.getParent().getParent().equals(getMxDefaultParent())
+//					srcCell.remove(dstCell.getParent());
+//					dstCell.getParent().setParent(mxDefaultParent);
+//					srcCell.setParent(dstCell.getParent());
+//					dstCell.getParent().insert(srcCell);
+					if (dstCell.getParent() != null
+							|| dstCell.getParent().getParent() != null
+							|| srcCell.getParent() != null
+							|| !dstCell.getParent().getParent().equals(getMxDefaultParent())
 							|| !srcCell.getParent().equals(dstCell.getParent())) {					
 						srcCell.remove(dstCell.getParent());
-						dstCell.getParent().remove(dstCell);
 						dstCell.getParent().setParent(getMxDefaultParent());
-						srcCell.getParent().remove(srcCell);
+						// TODO: Confirm why not need following comment out.
+//						dstCell.getParent().remove(dstCell);
+						// TODO: Confirm why not need following comment out.
+//						srcCell.getParent().remove(srcCell);
 						srcCell.setParent(dstCell.getParent());
 						dstCell.getParent().insert(srcCell);
 					}
@@ -737,8 +746,8 @@
 			vertexAnim.init(srcCell, 
 					dstCell.getGeometry().getX() - overlapWidth + (srcCellWidth * time), dstCell.getGeometry().getY()  - overlapHeight + (srcCellHeight * time), 
 					threadPoolExecutor);
-//					vertexAnim.play();
-//					sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//			vertexAnim.play();
+//			sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
 			vertexAnim.syncPlay();
 
 			// Test code (will be deleted)
@@ -819,7 +828,8 @@
 				//			srcCell.setParent(dstCell.getParent());
 				//			dstCell.getParent().insert(srcCell);
 				if (srcCell.getParent() == null || !srcCell.getParent().equals(dstCell.getParent())) {
-					if (srcCell.getParent() != null) srcCell.getParent().remove(srcCell);
+					// TODO: Confirm why not need following comment out.
+//					if (srcCell.getParent() != null) srcCell.getParent().remove(srcCell);
 					srcCell.setParent(dstCell.getParent());
 					dstCell.getParent().insert(srcCell);
 				}
@@ -844,8 +854,8 @@
 		vertexAnim.init(srcCell, 
 				dstCell.getGeometry().getX() - (srcCellWidth / Math.sqrt(3)) + (srcCellWidth * time), dstCell.getGeometry().getY() + dstCellHeight, 
 				threadPoolExecutor);
-//				vertexAnim.play();
-//				sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//		vertexAnim.play();
+//		sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
 		vertexAnim.syncPlay();
 
 		// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.
@@ -917,27 +927,27 @@
 				dstPt.setLocation(dstPt.getX() - (dstDim.getWidth() - curDim.getWidth()) / 2, dstPt.getY() - (dstDim.getHeight() - curDim.getHeight()) / 2);
 				// Test code (will be deleted)
 				System.out.println(TAG + ": Translate " + ovCell.getId() + ". Current point=" + ovCell.getGeometry().getPoint() + ", Destination Point=" + dstPt);
-//					deltaAnimation.setVertexAnimation(ovCell, dstPt);
-//					deltaAnimation.startVertexAnimation();
+//				deltaAnimation.setVertexAnimation(ovCell, dstPt);
+//				deltaAnimation.startVertexAnimation();
 				MagnetRONAnimation vertexAnim = new TranslateAnimation(mxgraph, getGraphComponent());
 				mxICellToTranslateAnimMap.put(ovCell, vertexAnim);
 				vertexAnim.setTotalCycleCount(10);
 				vertexAnim.setDelay(100);
 				vertexAnim.init(ovCell, dstPt.getX(), dstPt.getY(), threadPoolExecutor);
 				vertexAnim.play();
-//					sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
-//					deltaAnimation.setResizeVertexAnimation(ovCell, dstDim);
-//					deltaAnimation.startResizeVertexAnimation();
-//					deltaAnimation.sleepThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//				sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//				deltaAnimation.setResizeVertexAnimation(ovCell, dstDim);
+//				deltaAnimation.startResizeVertexAnimation();
+//				deltaAnimation.sleepThread(DEFAULT_THREAD_SLEEP_MILLIS);
 				MagnetRONAnimation vertexResizeAnim = new VertexResizeAnimation(mxgraph, getGraphComponent());
 				vertexResizeAnim.setTotalCycleCount(10);
 				vertexResizeAnim.setDelay(100);
 				vertexResizeAnim.init(ovCell, dstDim.getWidth(), dstDim.getHeight(), threadPoolExecutor);
 				vertexResizeAnim.play();
-//					sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
+//				sleepMainThread(DEFAULT_THREAD_SLEEP_MILLIS);
 				for (int i = 0; i < ovCell.getChildCount(); i++) {
 					mxICell childCell = ovCell.getChildAt(i);
-//						if (mxICellToTranslateAnimMap.get(childCell) != null) continue;
+//					if (mxICellToTranslateAnimMap.get(childCell) != null) continue;
 					double childCellCurX = childCell.getGeometry().getX();
 					double childCellCurY = childCell.getGeometry().getY();
 					Point2D childDstPt = 
@@ -1000,31 +1010,35 @@
 			time -= 1;
 		}
 
+		mxICell cell = null;
+		MethodExecutionVertex methodExecVertex = null;
 		// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.
 		mxgraph.getModel().beginUpdate();
 		synchronized (mxgraph.getModel()) {
 			try {
-				// Creates a white cell of {@code ObjectVertex}. 
-				mxICell cell = (mxICell) mxgraph.insertDeltaVertex(parentCell, methodSignature, methodSignature, "fillColor=white");
+				// Creates a white cell of MethodExecutionVertex. 
+				cell = (mxICell) mxgraph.insertDeltaVertex(parentCell, methodSignature, methodSignature, "fillColor=white");
 				mxgraph.orderCells(false, new Object[] {cell});
 				// Test code (will be deleted)
 				System.out.println("makeVertexMethodExecution: " + cell.getId() + " in " + objectId + " (" + stdX + ", " + coordY * (time + 1) + stdY + ")");
-	
-				MethodExecutionVertex methodExecVertex = 
+				methodExecVertex = 
 						new MethodExecutionVertex(methodSignature, cell, stdX, coordY * (time + 1) + stdY, 
 								DEFAULT_METHOD_EXECUTION_VERTEX_SIZE.getWidth(), DEFAULT_METHOD_EXECUTION_VERTEX_SIZE.getHeight());
 				methodExecToVertexMap.put(methodExecution, methodExecVertex);
 				if(methodExecToVertexMap.size() > 1) {
+					// Caution: If synchronized block is split here, {@code cell} display instantly until cell#setVisible(false) is executed.
 					cell.setVisible(false);
-					createEdgeToMethodExecution();
 				}
-				objectToVertexMap.get(objectId).addMethodExecution(methodExecVertex);
 			} finally {
 				mxgraph.getModel().endUpdate();
 			}
-//			setCellsStyle();
-			update();
 		}
+		if(methodExecToVertexMap.size() > 1) {
+			createEdgeToMethodExecution();
+		}
+		objectToVertexMap.get(objectId).addMethodExecution(methodExecVertex);
+//		setCellsStyle();
+		update();
 	}
 
 	/**
@@ -1159,7 +1173,7 @@
 	protected void removeCalledMethodExecutionVertex(ObjectVertex sourceObjectVertex, MethodExecution methodExecution, MethodExecution calledMethodExecution) {	
 		// Test code (will be deleted)
 		outputLog();
-
+//		MagnetRONAnimation.waitAnimationEnd();
 		//  Remove ObjectVertex other than sourceObjectVertex from locals and arguments of called MethodExecutionVertex.  
 		if (methodExecToVertexMap.containsKey(calledMethodExecution)) {
 			MethodExecutionVertex calledMethodExecVertex = methodExecToVertexMap.get(calledMethodExecution);
@@ -1315,14 +1329,15 @@
 								mxgraph.removeCells(new Object[]{clonedstMethodExecVertexCell[0]});
 
 								// TODO: Confirm execution order.
-//						dstMethodExecVertexCell.getParent().remove(dstMethodExecVertexCell);
-//						dstMethodExecVertexCell.setParent(mxDefaultParent);
+//								dstMethodExecVertexCell.getParent().remove(dstMethodExecVertexCell);
+//								dstMethodExecVertexCell.setParent(mxDefaultParent);
 								if (!dstMethodExecVertexCell.getParent().equals(getMxDefaultParent())) {
 									// If parent of ObjectVertex cell isn't mxDefaltParent, reset parent.
 									dstMethodExecVertexCell.getParent().remove(dstMethodExecVertexCell);
 									dstMethodExecVertexCell.setParent(getMxDefaultParent());
 								}
 								mxgraph.removeCells(new Object[] {dstMethodExecVertexCell});
+								update();
 							} finally {
 								mxgraph.getModel().endUpdate();
 							}
@@ -1338,12 +1353,11 @@
 				}
 				methodExecToVertexMap.get(calledMethodExecution).getLocals().remove(sourceObjectVertex);
 				methodExecToVertexMap.remove(calledMethodExecution);
-				edgeMap.remove(methodExecution.getSignature());		
-				
-				sleepMainThread(400);
+				edgeMap.remove(methodExecution.getSignature());						
 			} catch (CloneNotSupportedException e) {
 				e.printStackTrace();
-			} 		
+			}
+			sleepMainThread(POSTPONE_ANIMATION_MILLIS);
 		}
 
 		// Test code (will be deleted)
@@ -1405,10 +1419,10 @@
 									// Test code (will be deleted)
 									System.out.println("Stretch edge animation action performed. ");
 									mxICell edge = (mxICell) mxgraph.insertDeltaEdge(getMxDefaultParent(), methodSig, null, srcMethodExecVertexCell, dstMethodExecVertexCell);
-		//							edge.getParent().remove(edge);
-		//							edge.setParent(mxDefaultParent);
+//									edge.getParent().remove(edge);
+//									edge.setParent(mxDefaultParent);
 									if (!edge.getParent().equals(getMxDefaultParent())) {
-										// If parent of {@code Edge} cell isn't mxDefaltParent, reset parent.
+										// If parent of Edge cell isn't mxDefaltParent, reset parent.
 										edge.getParent().remove(edge);
 										edge.setParent(getMxDefaultParent());
 									}
@@ -1423,6 +1437,7 @@
 							}
 						}
 					});
+//					MagnetRONAnimation.waitAnimationEnd();
 					edgeAnim.play();
 					// Add a vertex to the graph in a transactional fashion. The vertex is actually a 'cell' in jgraphx terminology.
 					mxgraph.getModel().beginUpdate();
@@ -1433,11 +1448,11 @@
 							mxgraph.getModel().endUpdate();
 						}
 					}
-					sleepMainThread(400);
 				} catch (CloneNotSupportedException e) {
 					e.printStackTrace();
 				}
 			}
+			sleepMainThread(POSTPONE_ANIMATION_MILLIS);
 		}
 	}
 
@@ -1552,7 +1567,9 @@
 	protected Point2D getAbsolutePointforCell(mxICell cell) {
 		Point2D p1 = new Point2D.Double(cell.getGeometry().getX(), cell.getGeometry().getY());;
 //		if(cell.getParent().getValue() == null || cell == cell.getParent()) {
-		if(cell.getParent().getValue() == null || cell.equals(cell.getParent())) {
+		if(cell.getParent() == null 
+				|| cell.getParent().getValue() == null
+				|| cell.equals(cell.getParent())) {
 			return p1;
 		}
 		// Test code (will be deleted)
@@ -1768,7 +1785,7 @@
 	public void sleepMainThread(long millis) {
 		try {
 			// Test code (will be deleted)
-			System.out.println(TAG + ": Sleep Main thread " + millis + "millis.");
+			System.out.println(TAG + ": Sleep Main thread " + millis + "millis. ThreadId=" + Thread.currentThread().getId());
 			Thread.sleep(millis);
 			System.out.println(TAG + ": Resume Main thread.");
 		} catch (InterruptedException e) {