diff --git a/Instance.cpp b/Instance.cpp
index 99e1f5f..624f3a4 100644
--- a/Instance.cpp
+++ b/Instance.cpp
@@ -41,7 +41,7 @@ PROPGRIDITEM Instance::createPGI(LPSTR catalog, LPSTR propName, LPSTR propDesc,
 	return pItem;
 }
 
-void Instance::PropUpdate(LPPROPGRIDITEM item)
+void Instance::PropUpdate(LPPROPGRIDITEM &item)
 {
 	if(strcmp(item->lpszPropName, "Name") == 0)
 	{
diff --git a/Instance.h b/Instance.h
index 44eb41a..ad132e0 100644
--- a/Instance.h
+++ b/Instance.h
@@ -21,7 +21,7 @@ public:
 	Instance* getParent();
 	virtual Instance* clone() const { return new Instance(*this); }
 	virtual std::vector<PROPGRIDITEM> getProperties();
-	virtual void PropUpdate(LPPROPGRIDITEM pItem);
+	virtual void PropUpdate(LPPROPGRIDITEM &pItem);
 protected:
 	std::string className;
 	Instance* parent;  // Another pointer.
diff --git a/PhysicalInstance.cpp b/PhysicalInstance.cpp
index 5d98a63..0dbc596 100644
--- a/PhysicalInstance.cpp
+++ b/PhysicalInstance.cpp
@@ -214,7 +214,7 @@ PhysicalInstance::~PhysicalInstance(void)
 }
 
 
-void PhysicalInstance::PropUpdate(LPPROPGRIDITEM item)
+void PhysicalInstance::PropUpdate(LPPROPGRIDITEM &item)
 {
 	if(strcmp(item->lpszPropName, "Name") == 0)
 	{
diff --git a/PhysicalInstance.h b/PhysicalInstance.h
index 1e46b52..3c26b07 100644
--- a/PhysicalInstance.h
+++ b/PhysicalInstance.h
@@ -34,7 +34,7 @@ public:
 	Vector3 rotVelocity;
 	bool collides(Box);
 	virtual std::vector<PROPGRIDITEM> getProperties();
-	virtual void PropUpdate(LPPROPGRIDITEM pItem);
+	virtual void PropUpdate(LPPROPGRIDITEM &pItem);
 private:
 	Vector3 position;
 	Vector3 size;