diff --git a/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java b/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java
index fff5242..6f3a808 100644
--- a/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java
+++ b/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java
@@ -7,11 +7,14 @@
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.SortedSet;
+import java.util.TreeSet;
 import java.util.stream.Collectors;
 
 import org.ntlab.deltaExtractor.ExtractedStructure;
 import org.ntlab.trace.MethodExecution;
 import org.ntlab.trace.MethodInvocation;
+import org.ntlab.trace.ObjectReference;
 import org.ntlab.trace.Reference;
 import org.ntlab.trace.Statement;
 import org.ntlab.trace.TracePoint;
@@ -25,12 +28,14 @@
 	private Set<Reference> references = new HashSet<>();
 	private List<MethodExecution> startPoints = new ArrayList<>(); // Common ancestor point
 	private List<TracePoint> relatedPoints = new ArrayList<>();
+	private SortedSet<Long> timeStamps = new TreeSet<>();		// List of time stamps of related points
 
 	public CollaborationObjectCallGraph(ExtractedStructure e) {
 		references.addAll(e.getDelta().getSrcSide());
 		references.addAll(e.getDelta().getDstSide());
 		startPoints.add(e.getCoordinator());
 		relatedPoints.add(e.getRelatedTracePoint().duplicate());
+		timeStamps.add(getTimeStampOfRelatedPoint(e.getRelatedTracePoint(), e));
 	}
 
 	@Override
@@ -53,6 +58,11 @@
 		return null;
 	}
 
+	@Override
+	public SortedSet<Long> getTimeStamps() {
+		return timeStamps;
+	}
+	
 	/**
 	 * Merge ExtractedStructure not to overlap reference.
 	 * 
@@ -117,10 +127,12 @@
 		startPoints.clear();
 		startPoints.add(lca);
 
-		// Is it in time stamp order?
 		TracePoint otherRelatedTp = e.getRelatedTracePoint().duplicate();
-		relatedPoints.add(otherRelatedTp);
-		relatedPoints = sortTracePointByTimeStamp(relatedPoints);
+		long rpTimeStamp = getTimeStampOfRelatedPoint(otherRelatedTp, e);
+		int idx = timeStamps.headSet(rpTimeStamp).size();
+		relatedPoints.add(idx, otherRelatedTp);
+		timeStamps.add(rpTimeStamp);
+//		relatedPoints = sortTracePointByTimeStamp(relatedPoints);
 	}
 
 	/**
@@ -147,6 +159,23 @@
 		}
 		return qTmp;
 	}
+	
+	private Long getTimeStampOfRelatedPoint(TracePoint relatedTracePoint, ExtractedStructure e) {
+		ObjectReference targetObj = null;
+		if (e.getDelta().getDstSide().size() > 0) {
+			targetObj = e.getDelta().getDstSide().get(0).getDstObject();
+		} else {
+			targetObj = new ObjectReference(e.getCoordinator().getThisObjId(), e.getCoordinator().getThisClassName());
+		}
+		if (relatedTracePoint.isMethodEntry() && relatedTracePoint.getMethodExecution().getArguments().contains(targetObj)) {
+			return relatedTracePoint.getMethodExecution().getEntryTime();
+		}
+		if (relatedTracePoint.getStatement() instanceof MethodInvocation) {
+			return ((MethodInvocation) relatedTracePoint.getStatement()).getCalledMethodExecution().getExitTime();
+		} else {
+			return relatedTracePoint.getStatement().getTimeStamp();
+		}
+	}
 
 	/**
 	 * Sort TracePoint in time stamp order.
diff --git a/src/org/ntlab/deltaViewer/CollaborationViewer.java b/src/org/ntlab/deltaViewer/CollaborationViewer.java
index b2b0cf8..10fc087 100644
--- a/src/org/ntlab/deltaViewer/CollaborationViewer.java
+++ b/src/org/ntlab/deltaViewer/CollaborationViewer.java
@@ -99,12 +99,15 @@
 
 			if (numFrameAlias != null) {
 				if (curFrameAlias != null) {
-					for (TracePoint rp: relatedPoints) {
-						if (curFrameAlias.getTimeStamp() < rp.getStatement().getTimeStamp() && rp.getStatement().getTimeStamp() < numFrameAlias.getTimeStamp()) {
+					int i = 0;
+					for (Long rpTime:objectCallGraph.getTimeStamps()) {
+						if (curFrameAlias.getTimeStamp() <= rpTime && rpTime < numFrameAlias.getTimeStamp()) {
 							System.out.println("\r\n" + TAG + ": Last Animation.");
+							TracePoint rp = relatedPoints.get(i);
 							doLastAnimation(numFrame, rp);	
 							return;
 						}
+						i++;
 					}
 				}
 				doAnimation(curFrame, numFrame);
diff --git a/src/org/ntlab/deltaViewer/DeltaObjectCallGraph.java b/src/org/ntlab/deltaViewer/DeltaObjectCallGraph.java
index b90d9f2..2983e6c 100644
--- a/src/org/ntlab/deltaViewer/DeltaObjectCallGraph.java
+++ b/src/org/ntlab/deltaViewer/DeltaObjectCallGraph.java
@@ -3,9 +3,13 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.SortedSet;
+import java.util.TreeSet;
 
 import org.ntlab.deltaExtractor.ExtractedStructure;
 import org.ntlab.trace.MethodExecution;
+import org.ntlab.trace.MethodInvocation;
+import org.ntlab.trace.ObjectReference;
 import org.ntlab.trace.Reference;
 import org.ntlab.trace.TracePoint;
 
@@ -13,12 +17,14 @@
 	private List<Reference> references = new ArrayList<>();
 	private List<MethodExecution> startPoints = new ArrayList<>();
 	private List<TracePoint> relatedPoints = new ArrayList<>();
+	private SortedSet<Long> timeStamps = new TreeSet<>();		// List of time stamps of related points
 
 	public DeltaObjectCallGraph(ExtractedStructure e) {
 		references.addAll(e.getDelta().getSrcSide());
 		references.addAll(e.getDelta().getDstSide());
 		startPoints.add(e.getCoordinator());
 		relatedPoints.add(e.getRelatedTracePoint());
+		timeStamps.add(getTimeStampOfRelatedPoint(e.getRelatedTracePoint(), e));
 	}
 
 	@Override
@@ -42,4 +48,26 @@
 		// TODO Auto-generated method stub
 		return null;
 	}
+
+	@Override
+	public SortedSet<Long> getTimeStamps() {
+		return timeStamps;
+	}
+	
+	private Long getTimeStampOfRelatedPoint(TracePoint relatedTracePoint, ExtractedStructure e) {
+		ObjectReference targetObj = null;
+		if (e.getDelta().getDstSide().size() > 0) {
+			targetObj = e.getDelta().getDstSide().get(0).getDstObject();
+		} else {
+			targetObj = new ObjectReference(e.getCoordinator().getThisObjId(), e.getCoordinator().getThisClassName());
+		}
+		if (relatedTracePoint.isMethodEntry() && relatedTracePoint.getMethodExecution().getArguments().contains(targetObj)) {
+			return relatedTracePoint.getMethodExecution().getEntryTime();
+		}
+		if (relatedTracePoint.getStatement() instanceof MethodInvocation) {
+			return ((MethodInvocation) relatedTracePoint.getStatement()).getCalledMethodExecution().getExitTime();
+		} else {
+			return relatedTracePoint.getStatement().getTimeStamp();
+		}
+	}
 }
diff --git a/src/org/ntlab/deltaViewer/ForwardAliasCollector.java b/src/org/ntlab/deltaViewer/ForwardAliasCollector.java
index f0d48e1..8782053 100644
--- a/src/org/ntlab/deltaViewer/ForwardAliasCollector.java
+++ b/src/org/ntlab/deltaViewer/ForwardAliasCollector.java
@@ -3,6 +3,8 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import java.util.SortedSet;
+import java.util.TreeSet;
 
 import org.ntlab.deltaExtractor.Alias;
 import org.ntlab.deltaExtractor.Alias.AliasType;
@@ -188,6 +190,7 @@
 		private List<Reference> references = new ArrayList<>();
 		private List<MethodExecution> startPoints = new ArrayList<>();
 		private List<TracePoint> relatedPoints = new ArrayList<>();
+		private SortedSet<Long> timeStamps = new TreeSet<>();		// List of time stamps of related points
 		
 		public void addReference(Reference r) {
 			if (!references.contains(r)) references.add(r);
@@ -199,6 +202,7 @@
 		
 		public void addRelatedPoint(TracePoint tp) {
 			relatedPoints.add(tp);
+			timeStamps.add(tp.getStatement().getTimeStamp());		// Will not work when a formal parameter is passed and related to this object.
 		}
 
 		@Override
@@ -220,6 +224,11 @@
 		public Map<MethodExecution, List<MethodExecution>> getCallTree() {
 			return null;
 		}
+
+		@Override
+		public SortedSet<Long> getTimeStamps() {
+			return null;
+		}
 		
 	}
 }
diff --git a/src/org/ntlab/deltaViewer/IObjectCallGraph.java b/src/org/ntlab/deltaViewer/IObjectCallGraph.java
index 91d7be5..8073ab5 100644
--- a/src/org/ntlab/deltaViewer/IObjectCallGraph.java
+++ b/src/org/ntlab/deltaViewer/IObjectCallGraph.java
@@ -2,6 +2,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.SortedSet;
 
 import org.ntlab.trace.MethodExecution;
 import org.ntlab.trace.Reference;
@@ -17,6 +18,8 @@
 	List<MethodExecution> getStartPoints();
 
 	List<TracePoint> getRelatedPoints();
+	
+	SortedSet<Long> getTimeStamps();
 
 	Map<MethodExecution, List<MethodExecution>> getCallTree();
 }