diff --git a/src/org/ntlab/deltaExtractor/DeltaExtractor.java b/src/org/ntlab/deltaExtractor/DeltaExtractor.java
index 36291dd..794b9a4 100644
--- a/src/org/ntlab/deltaExtractor/DeltaExtractor.java
+++ b/src/org/ntlab/deltaExtractor/DeltaExtractor.java
@@ -336,6 +336,15 @@
 								} else {
 									aliasCollector.addAlias(new DeltaAlias(Alias.AliasType.RECEIVER, 0, objList.get(retIndex), tracePoint.duplicate(), false));
 								}
+							} else if (objList.get(retIndex) == null) {
+								// static �Ăяo���������ꍇ
+								removeList.add(thisObjectId);		// ��ň�U�AthisObject ����菜��
+								isTrackingThis = true;				// �Ăяo�����T���O�ɕ���
+								if (isSrcSide) {
+									aliasCollector.addAlias(new DeltaAlias(Alias.AliasType.THIS, 0, thisObjectId, tracePoint.duplicate(), true));
+								} else {
+									aliasCollector.addAlias(new DeltaAlias(Alias.AliasType.THIS, 0, thisObjectId, tracePoint.duplicate(), false));
+								}
 							}
 							if (isLost) {
 								checkList.add(objList.get(retIndex));
diff --git a/src/org/ntlab/deltaExtractor/DeltaExtractorJSON.java b/src/org/ntlab/deltaExtractor/DeltaExtractorJSON.java
index 4332284..6837abf 100644
--- a/src/org/ntlab/deltaExtractor/DeltaExtractorJSON.java
+++ b/src/org/ntlab/deltaExtractor/DeltaExtractorJSON.java
@@ -247,6 +247,11 @@
 									isTrackingThis = true;				// �Ăяo�����T���O�ɕ���
 								}
 								aliasCollector.addAlias(new Alias(Alias.AliasType.RECEIVER, 0, objList.get(retIndex), tracePoint.duplicate()));
+							} else if (objList.get(retIndex) == null) {
+								// static �Ăяo���������ꍇ
+								removeList.add(thisObjectId);		// ��ň�U�AthisObject ����菜��
+								isTrackingThis = true;				// �Ăяo�����T���O�ɕ���
+								aliasCollector.addAlias(new Alias(Alias.AliasType.THIS, 0, thisObjectId, tracePoint.duplicate()));
 							}
 							if (isLost) {
 								checkList.add(objList.get(retIndex));
diff --git a/src/org/ntlab/deltaViewer/CollaborationLayout.java b/src/org/ntlab/deltaViewer/CollaborationLayout.java
index 76674f9..30f331b 100644
--- a/src/org/ntlab/deltaViewer/CollaborationLayout.java
+++ b/src/org/ntlab/deltaViewer/CollaborationLayout.java
@@ -115,18 +115,6 @@
 					String srcClassName = methodExec.getThisClassName();
 					String dstClassName = methodExec.getReturnValue().getActualType();
 					idx = references.indexOf(new Reference(srcObjId, dstObjId, srcClassName, dstClassName));
-				} else if (methodExec.isStatic() && methodExec.getCallerMethodExecution().isStatic()) {
-					// For calls from a static method to another static method.
-					String dstClassName = methodExec.getThisClassName();
-					String srcClassName = methodExec.getCallerMethodExecution().getThisClassName();
-					String dstObjId = methodExec.getThisObjId() + ":" + dstClassName;
-					String srcObjId = methodExec.getCallerMethodExecution().getThisObjId() + ":" + srcClassName;
-					Reference r = new Reference(srcObjId, dstObjId, srcClassName, dstClassName);
-					idx = references.indexOf(r);
-					if (idx < 0) {
-						references.add(r);
-						idx = references.indexOf(r);
-					}					
 				}
 			} else if (a.getAliasType() == AliasType.CONSTRACTOR_INVOCATION) {
 				MethodInvocation c = (MethodInvocation) a.getOccurrencePoint().getStatement();
@@ -140,6 +128,29 @@
 				String srcObjId = a.getMethodExecution().getThisObjId();
 				String srcClassName = a.getMethodExecution().getThisClassName();
 				idx = references.indexOf(new Reference(srcObjId, ac.getArrayObjectId(), srcClassName, ac.getArrayClassName()));
+			} else if (a.getAliasType() == AliasType.THIS) {
+				Statement st = a.getOccurrencePoint().getStatement();
+				if (st instanceof MethodInvocation) {
+					MethodExecution methodExec = ((MethodInvocation) st).getCalledMethodExecution();
+					if (methodExec.isStatic()) {
+						// For calls to a static method.
+						String dstClassName = methodExec.getThisClassName();
+						String srcClassName = methodExec.getCallerMethodExecution().getThisClassName();
+						String dstObjId = methodExec.getThisObjId() + ":" + dstClassName;
+						String srcObjId = null;
+						if (!a.getMethodExecution().isStatic()) {
+							srcObjId = methodExec.getCallerMethodExecution().getThisObjId();
+						} else {
+							srcObjId = methodExec.getCallerMethodExecution().getThisObjId() + ":" + srcClassName;							
+						}
+						Reference r = new Reference(srcObjId, dstObjId, srcClassName, dstClassName);
+						idx = references.indexOf(r);
+						if (idx < 0) {
+							references.add(r);
+							idx = references.indexOf(r);
+						}					
+					}
+				}
 			}
 			if (idx >= 0) {
 				Reference r = references.get(idx);