diff --git a/src/org/ntlab/traceDebugger/Variable.java b/src/org/ntlab/traceDebugger/Variable.java
index aecfe18..60e2185 100644
--- a/src/org/ntlab/traceDebugger/Variable.java
+++ b/src/org/ntlab/traceDebugger/Variable.java
@@ -45,7 +45,7 @@
 	public enum VariableType {
 		USE_VALUE, USE_CONTAINER, USE_RECEIVER, USE_RETURN,
 		DEF_VALUE, DEF_CONTAINER, DEF_RECEIVER, DEF_ARG, 
-		PARAMETER;
+		THIS, PARAMETER;
 		public boolean isContainerSide() {
 			return this.equals(USE_CONTAINER) || this.equals(DEF_CONTAINER) 
 					|| this.equals(USE_RECEIVER) || this.equals(DEF_RECEIVER);
diff --git a/src/org/ntlab/traceDebugger/VariableLabelProvider.java b/src/org/ntlab/traceDebugger/VariableLabelProvider.java
index 3869875..8c2dbfa 100644
--- a/src/org/ntlab/traceDebugger/VariableLabelProvider.java
+++ b/src/org/ntlab/traceDebugger/VariableLabelProvider.java
@@ -80,8 +80,8 @@
 				return registry.getDescriptor(SPECIAL_VARIABLE).createImage();
 			} else if (value instanceof Variable) {
 				Variable variable = (Variable)value;
-				VariableType variableType = variable.getVariableType();
-				if (variable.getVariableName().equals("this")) {
+				VariableType variableType = variable.getVariableType();				
+				if (variableType == VariableType.THIS) {
 					return registry.getDescriptor(THIS_VARIABLE).createImage();
 				} else if (variableType == VariableType.PARAMETER){
 					return registry.getDescriptor(ARG_VARIABLE).createImage();
diff --git a/src/org/ntlab/traceDebugger/Variables.java b/src/org/ntlab/traceDebugger/Variables.java
index e9ae236..a389269 100644
--- a/src/org/ntlab/traceDebugger/Variables.java
+++ b/src/org/ntlab/traceDebugger/Variables.java
@@ -75,7 +75,8 @@
 		String thisObjId = methodExecution.getThisObjId();
 		String thisClassName = methodExecution.getThisClassName();
 		if (before == null) before = tp;
-		Variable variable = new Variable("this", null, null, thisClassName, thisObjId, before, isReturned);
+//		Variable variable = new Variable("this", null, null, thisClassName, thisObjId, before, isReturned);
+		Variable variable = new Variable("this", null, null, thisClassName, thisObjId, before, isReturned, VariableType.THIS);
 		roots.add(variable);
 		variable.createNextHierarchyState();
 	}