diff --git a/Library/Measure.cpp b/Library/Measure.cpp
index 6a5e7fa5..aee513ba 100644
--- a/Library/Measure.cpp
+++ b/Library/Measure.cpp
@@ -758,6 +758,10 @@ void CMeasure::DoChangeAction(bool execute)
 	{
 		double newValue = GetValue();
 		const WCHAR* newStringValue = GetStringValue();
+		if (!newStringValue)
+		{
+			newStringValue = L"";
+		}
 
 		if (!m_OldValue)
 		{
diff --git a/Library/Measure.h b/Library/Measure.h
index 183424d3..91abe170 100644
--- a/Library/Measure.h
+++ b/Library/Measure.h
@@ -40,34 +40,9 @@ enum AUTOSCALE
 class CMeasureValueSet
 {
 public:
-	CMeasureValueSet(double val, const WCHAR* str) : m_Value(val), m_StringValue(str ? str : L"") {}
-
-	void Set(double val, const WCHAR* str)
-	{
-		m_Value = val;
-		if (str)
-		{
-			m_StringValue = str;
-		}
-		else
-		{
-			m_StringValue.clear();
-		}
-	}
-
-	bool IsChanged(double val, const WCHAR* str)
-	{
-		if (m_Value != val ||
-			(!str && !m_StringValue.empty()) ||
-			(str && wcscmp(m_StringValue.c_str(), str) != 0))
-		{
-			Set(val, str);
-			return true;
-		}
-		
-		return false;
-	}
-
+	CMeasureValueSet(double val, const WCHAR* str) : m_Value(val), m_StringValue(str) {}
+	void Set(double val, const WCHAR* str) { m_Value = val; m_StringValue = str; }
+	bool IsChanged(double val, const WCHAR* str) { if (m_Value != val || wcscmp(m_StringValue.c_str(), str) != 0) { Set(val, str); return true; } return false; }
 private:
 	double m_Value;
 	std::wstring m_StringValue;