diff --git a/src/org/ntlab/deltaViewer/CollaborationAliasCollector.java b/src/org/ntlab/deltaViewer/CollaborationAliasCollector.java
index 9f22d79..979f5f7 100644
--- a/src/org/ntlab/deltaViewer/CollaborationAliasCollector.java
+++ b/src/org/ntlab/deltaViewer/CollaborationAliasCollector.java
@@ -7,6 +7,7 @@
 
 import org.ntlab.deltaExtractor.Alias;
 import org.ntlab.deltaExtractor.IAliasCollector;
+import org.ntlab.featureExtractor.Extract;
 
 /**
  * CollaborationAliasCollector is IAliasCollector implementation class to merge aliasList in time stamp order.
@@ -37,15 +38,25 @@
 	/**
 	 * Merge other into aliasList(this) in time stamp order.
 	 * @param other�@IAliasCollector to be merged into the aliasList.
+	 * @param extract 
 	 */
-	public void merge(IAliasCollector other) {
+	public void merge(IAliasCollector other, Extract extract) {
 		List<Alias> otherAliasList = other.getAliasList();
 		otherAliasList = sortAliasListByTimeStamp(otherAliasList);
-		int otherIdx = 0; // Index of otherAliasList
-		int thisIdx = 0; // Index of thisAliasList
+		int otherIdx = 0; // Index in otherAliasList
+		int thisIdx = 0; // Index in thisAliasList
+		int thisOrgIdx = 0; // Index in the original thisAliasList
 		while(otherIdx < otherAliasList.size()) {
 			Alias otherAlias = otherAliasList.get(otherIdx);
 			if (thisIdx >= aliasList.size()) {
+				if (extract != null && extract.isToConnect() && otherIdx == 0) {
+					Alias thisPrevAlias = aliasList.get(aliasList.size() - 1);
+					if (!otherAlias.getMethodExecution().isStatic() && otherAlias.getMethodExecution().getCallerMethodExecution() != thisPrevAlias.getMethodExecution()) {
+						// Add a dummy alias to connect disjunct call hierarchies.
+						aliasList.add(new Alias(Alias.AliasType.RECEIVER, 0, otherAlias.getMethodExecution().getThisObjId(), thisPrevAlias.getOccurrencePoint()));
+						thisIdx++;
+					}
+				}
 				aliasList.add(otherAlias);
 				otherIdx++; thisIdx++;
 				continue;
@@ -53,16 +64,32 @@
 			
 			Alias thisAlias = aliasList.get(thisIdx);
 			if (otherAlias.equals(thisAlias)) {
-				otherIdx++; thisIdx++;
+				otherIdx++; thisIdx++; thisOrgIdx++;
 			} else {
 				long otherAliasTs = otherAlias.getTimeStamp();
 				long thisAliasTs = thisAlias.getTimeStamp();
 				
 				if (otherAliasTs < thisAliasTs) {
+					if (extract != null && extract.isToConnect() && otherIdx == 0 && thisIdx > 0) {
+						Alias thisPrevAlias = aliasList.get(thisIdx - 1);
+						if (!otherAlias.getMethodExecution().isStatic() && otherAlias.getMethodExecution().getCallerMethodExecution() != thisPrevAlias.getMethodExecution()) {
+							// Add a dummy alias to connect disjunct call hierarchies.
+							aliasList.add(thisIdx, new Alias(Alias.AliasType.RECEIVER, 0, otherAlias.getMethodExecution().getThisObjId(), thisPrevAlias.getOccurrencePoint()));
+							thisIdx++;
+						}
+					}
 					aliasList.add(thisIdx, otherAlias);
 					otherIdx++; thisIdx++;
 				} else if (otherAliasTs > thisAliasTs) {
-					thisIdx++;
+					if (extract != null && extract.isToConnect() && thisOrgIdx == 0 && otherIdx > 0) {
+						Alias otherPrevAlias = otherAliasList.get(otherIdx - 1);
+						if (!thisAlias.getMethodExecution().isStatic() && thisAlias.getMethodExecution().getCallerMethodExecution() != otherPrevAlias.getMethodExecution()) {
+							// Add a dummy alias to connect disjunct call hierarchies.
+							aliasList.add(thisIdx, new Alias(Alias.AliasType.RECEIVER, 0, thisAlias.getMethodExecution().getThisObjId(), otherPrevAlias.getOccurrencePoint()));
+							thisIdx++;
+						}
+					}
+					thisIdx++; thisOrgIdx++;
 				} else {
 					if (aliasList.contains(otherAlias)) {
 						otherIdx++;
@@ -74,6 +101,14 @@
 				}
 			}
 		}
+		if (extract != null && extract.isToConnect() && thisOrgIdx == 0 && otherIdx > 0 && thisIdx < aliasList.size()) {
+			Alias thisAlias = aliasList.get(thisIdx);
+			Alias otherPrevAlias = otherAliasList.get(otherIdx - 1);
+			if (!thisAlias.getMethodExecution().isStatic() && thisAlias.getMethodExecution().getCallerMethodExecution() != otherPrevAlias.getMethodExecution()) {
+				// Add a dummy alias to connect disjunct call hierarchies.
+				aliasList.add(thisIdx, new Alias(Alias.AliasType.RECEIVER, 0, thisAlias.getMethodExecution().getThisObjId(), otherPrevAlias.getOccurrencePoint()));
+			}
+		}
 	}
 	
 	/**
diff --git a/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java b/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java
index adda005..16f3d4b 100644
--- a/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java
+++ b/src/org/ntlab/deltaViewer/CollaborationObjectCallGraph.java
@@ -106,6 +106,13 @@
 		thisRoot = tmp;
 		/* lowest common ancestor algorithm */
 		MethodExecution lca = lowestCommonAncestor(thisRoot, thisStartPoint, otherStartPoint);
+		if (lca == null) {
+			if (thisStartPoint.getEntryTime() < otherStartPoint.getEntryTime()) {
+				lca = thisStartPoint;
+			} else {
+				lca = otherStartPoint;
+			}
+		}
 		startPoints.clear();
 		startPoints.add(lca);
 
@@ -136,7 +143,7 @@
 			if (pRoots.contains(qTmp)) return qTmp;
 			qTmp = qTmp.getParent();
 		}
-		return root;
+		return qTmp;
 	}
 
 	/**
diff --git a/src/org/ntlab/deltaViewer/MagnetRONFrame.java b/src/org/ntlab/deltaViewer/MagnetRONFrame.java
index fa86c7f..3601a8f 100644
--- a/src/org/ntlab/deltaViewer/MagnetRONFrame.java
+++ b/src/org/ntlab/deltaViewer/MagnetRONFrame.java
@@ -213,7 +213,7 @@
 			if (cac == null) {
 				cac = new CollaborationAliasCollector(dac);
 			} else {
-				cac.merge(dac);
+				cac.merge(dac, extract);
 			}
 		}
 		cocg.shrinkAll(newToOldMethodExecMap);
@@ -255,7 +255,7 @@
 			if (cac == null) {
 				cac = new CollaborationAliasCollector(dac);
 			} else {
-				cac.merge(dac);
+				cac.merge(dac, null);
 			}
 		}
 		cocg.shrinkAll(newToOldMethodExecMap);
diff --git a/src/org/ntlab/featureExtractor/Extract.java b/src/org/ntlab/featureExtractor/Extract.java
index b74bff0..8c10c25 100644
--- a/src/org/ntlab/featureExtractor/Extract.java
+++ b/src/org/ntlab/featureExtractor/Extract.java
@@ -16,13 +16,16 @@
 	
 	private int order = 0;
 	
-	public Extract(String srcId, String srcClass, String dstId, String dstClass, String type, int order) {
+	private boolean toConnect = false;
+	
+	public Extract(String srcId, String srcClass, String dstId, String dstClass, String type, int order, boolean toConnect) {
 		this.srcId = srcId;
 		this.srcClass = srcClass;
 		this.dstId = dstId;
 		this.dstClass = dstClass;
 		this.type = type;
 		this.order = order;
+		this.toConnect = toConnect;
 	}
 
 	public String getSrcId() {
@@ -49,4 +52,7 @@
 		return order;
 	}
 
+	public boolean isToConnect() {
+		return toConnect;
+	}
 }
diff --git a/src/org/ntlab/featureExtractor/MagnetronParser.java b/src/org/ntlab/featureExtractor/MagnetronParser.java
index 14e284e..43bee98 100644
--- a/src/org/ntlab/featureExtractor/MagnetronParser.java
+++ b/src/org/ntlab/featureExtractor/MagnetronParser.java
@@ -125,13 +125,17 @@
 		Map<String, Object> srcObject = (Map<String, Object>) object.get("src");
 		Map<String, Object> dstObject = (Map<String, Object>) object.get("dst");
 		int order = Integer.parseInt((String) object.get("order"));
+		boolean isToConnect = false;
+		if (object.get("connect") != null) {
+			isToConnect = (Boolean) object.get("connect");
+		}
 		Extract extract = new Extract(
 				(String) srcObject.get("id"), 
 				(String) srcObject.get("class"), 
 				(String) dstObject.get("id"), 
 				(String) dstObject.get("class"), 
 				(String) object.get("type"), 
-				order);
+				order, isToConnect);
 		extracts.add(extract);		
 		return residual;
 	}
@@ -194,6 +198,12 @@
 		} else if (line.startsWith("null")) {
 			residual = line.substring(4);
 			values[0] = null;
+		} else if (line.startsWith("true")) {
+			residual = line.substring(4);
+			values[0] = true;
+		} else if (line.startsWith("false")) {
+			residual = line.substring(5);
+			values[0] = false;
 		} else {
 			// To Do
 		}
diff --git a/src/tests/CollaborationAliasCollectorTest.java b/src/tests/CollaborationAliasCollectorTest.java
index c0d52cf..f1eb166 100644
--- a/src/tests/CollaborationAliasCollectorTest.java
+++ b/src/tests/CollaborationAliasCollectorTest.java
@@ -30,7 +30,7 @@
 			if (cac == null) {
 				cac = new CollaborationAliasCollector(dac);
 			} else {
-				cac.merge(dac);
+				cac.merge(dac, null);
 			}
 		}
 		System.out.println("mergedAliasList: ");
diff --git a/src/tests/CollaborationObjectCallGraphTest.java b/src/tests/CollaborationObjectCallGraphTest.java
index 3ed9123..d6a8454 100644
--- a/src/tests/CollaborationObjectCallGraphTest.java
+++ b/src/tests/CollaborationObjectCallGraphTest.java
@@ -46,7 +46,7 @@
 				if (cac == null) {
 					cac = new CollaborationAliasCollector(dac);
 				} else {
-					cac.merge(dac);
+					cac.merge(dac, null);
 				}
 			}
 		}
diff --git a/src/tests/MagnetRONFrameTest.java b/src/tests/MagnetRONFrameTest.java
index 700ec10..4e92d54 100644
--- a/src/tests/MagnetRONFrameTest.java
+++ b/src/tests/MagnetRONFrameTest.java
@@ -85,7 +85,7 @@
 				if (cac == null) {
 					cac = new CollaborationAliasCollector(dac);
 				} else {
-					cac.merge(dac);
+					cac.merge(dac, null);
 				}
 			}
 //			new Thread() {
diff --git a/traces/EclipseDebug.magnet b/traces/EclipseDebug.magnet
index dff8124..7200715 100644
--- a/traces/EclipseDebug.magnet
+++ b/traces/EclipseDebug.magnet
@@ -7,6 +7,18 @@
       "extracts": [
         {
           "src": {
+            "class": "public void org.eclipse.jdt.internal.debug.core.EventDispatcher.run(",
+            "id": "629542817"
+          }, 
+          "dst": {
+            "class": "org.eclipse.jdi.internal.event.EventSetImpl",
+            "id": "1400795012"
+          }, 
+          "type": "This-Another", 
+          "order": "0"
+        },
+        {
+          "src": {
             "class": "public boolean org.eclipse.jdt.internal.debug.core.breakpoints.JavaBreakpoint.handleBreakpointEvent(",
             "id": "666051245"
           }, 
@@ -15,7 +27,8 @@
             "id": "907205473"
           }, 
           "type": "This-Another",
-          "order": "0"
+          "order": "0",
+          "connect": true
         },
         {
           "src": {
@@ -41,18 +54,6 @@
           "type": "Container-Component(Collection)",
           "order": "0"
         },
-        {
-          "src": {
-            "class": "public void org.eclipse.jdt.internal.debug.core.EventDispatcher.run(",
-            "id": "629542817"
-          }, 
-          "dst": {
-            "class": "org.eclipse.jdi.internal.event.EventSetImpl",
-            "id": "1400795012"
-          }, 
-          "type": "This-Another", 
-          "order": "0"
-        },
       	{
           "src": {
             "class": "public com.sun.jdi.event.EventSet org.eclipse.jdi.internal.event.EventQueueImpl.remove(",