diff --git a/src/org/ntlab/traceDebugger/DebuggingController.java b/src/org/ntlab/traceDebugger/DebuggingController.java
index 755d204..0d7790b 100644
--- a/src/org/ntlab/traceDebugger/DebuggingController.java
+++ b/src/org/ntlab/traceDebugger/DebuggingController.java
@@ -285,7 +285,7 @@
 		refresh(null, debuggingTp, false);
 		return true;
 	}
-	
+
 	public boolean stepOverAction() {
 		if (!isRunning) return false;
 		if (debuggingTp == null) return false;
@@ -298,28 +298,13 @@
 		int currentLineNo = debuggingTp.getStatement().getLineNo();
 		boolean isReturned = false;
 
-		// �X�e�b�v�I�[�o�[��p���ē��B�_�����‚��Ă���
-		TracePoint startTp = debuggingTp.duplicate();
 		while (!(isReturned = !(debuggingTp.stepOver()))) {
 			if (currentLineNo != debuggingTp.getStatement().getLineNo()) break;
 			previousTp = debuggingTp.duplicate();
 		}
-		TracePoint goalTp = debuggingTp.duplicate();
-		if (!isReturned) {
-			// �X�e�b�v�t����p���č��x�͌Ăяo����ɂ�����Ȃ���\�ߌ��‚��Ă��������B�_�܂Ői�܂��� (�ϐ������X�V�̂��ߓr���̃A�b�v�f�[�g��S�ďE��)
-			debuggingTp = startTp;
-			do {
-				Statement statement = debuggingTp.getStatement();
-				if (statement.equals(goalTp.getStatement())) break;
-				if (statement instanceof FieldUpdate || statement instanceof ArrayUpdate) {
-					Variables.getInstance().addDifferentialUpdatePoint(debuggingTp);
-				}
-			} while (debuggingTp.stepFull());			
-		} else {
-			debuggingTp = goalTp;
+		if (isReturned) {
 			while (!debuggingTp.stepOver()); // �Ăяo�����ł̎��̃X�e�[�g�����g�܂Ői�߂�
 		}
-
 		if (debugExecutionIsTerminated(debuggingTp)) return false;
 		refresh(previousTp, debuggingTp, isReturned, true);
 		return true;
@@ -345,7 +330,7 @@
 		refresh(previousTp, debuggingTp, true);
 		return true;
 	}
-	
+
 	public boolean stepNextAction() {
 		if (!isRunning) return false;
 		if (debuggingTp == null) return false;
@@ -355,27 +340,13 @@
 		}
 		TracePoint previousTp = debuggingTp;
 		debuggingTp = debuggingTp.duplicate();
-		TracePoint startTp = debuggingTp.duplicate();
 		boolean isReturned = !(debuggingTp.stepNext());
-		TracePoint goalTp = debuggingTp.duplicate();
-		if (!isReturned) {
-			// �X�e�b�v�t����p���č��x�͌Ăяo����ɂ�����Ȃ���\�ߌ��‚��Ă��������B�_�܂Ői�܂��� (�ϐ������X�V�̂��ߓr���̃A�b�v�f�[�g��S�ďE��)
-			debuggingTp = startTp;
-			do {
-				Statement statement = debuggingTp.getStatement();
-				if (statement.equals(goalTp.getStatement())) break;
-				if (statement instanceof FieldUpdate || statement instanceof ArrayUpdate) {
-					Variables.getInstance().addDifferentialUpdatePoint(debuggingTp);
-				}
-			} while (debuggingTp.stepFull());			
-		} else {
-			debuggingTp = startTp;
+		if (isReturned) {
 			while (!debuggingTp.stepOver()); // �Ăяo�����ł̎��̃X�e�[�g�����g�܂Ői�߂�
 		}
-
 		if (debugExecutionIsTerminated(debuggingTp)) return false;
 		refresh(previousTp, debuggingTp, isReturned, true);
-		return true;	
+		return true;
 	}
 	
 	public boolean resumeAction() {