diff --git a/Library/ConfigParser.cpp b/Library/ConfigParser.cpp
index bb988e71..8ec7fd7e 100644
--- a/Library/ConfigParser.cpp
+++ b/Library/ConfigParser.cpp
@@ -672,12 +672,18 @@ const std::wstring& CConfigParser::ReadString(LPCTSTR section, LPCTSTR key, LPCT
 	return result;
 }
 
-bool CConfigParser::IsValueDefined(LPCTSTR section, LPCTSTR key)
+bool CConfigParser::IsKeyDefined(LPCTSTR section, LPCTSTR key)
 {
 	ReadString(section, key, L"", false);
 	return !m_LastDefaultUsed;
 }
 
+bool CConfigParser::IsValueDefined(LPCTSTR section, LPCTSTR key)
+{
+	const std::wstring& result = ReadString(section, key, L"", false);
+	return (!m_LastDefaultUsed && !result.empty());
+}
+
 void CConfigParser::AddMeasure(CMeasure* pMeasure)
 {
 	if (pMeasure)
diff --git a/Library/ConfigParser.h b/Library/ConfigParser.h
index 82cecc2f..9335a1ec 100644
--- a/Library/ConfigParser.h
+++ b/Library/ConfigParser.h
@@ -52,6 +52,7 @@ public:
 	void ResetMonitorVariables(CMeterWindow* meterWindow = NULL);
 
 	const std::wstring& ReadString(LPCTSTR section, LPCTSTR key, LPCTSTR defValue, bool bReplaceMeasures = true);
+	bool IsKeyDefined(LPCTSTR section, LPCTSTR key);
 	bool IsValueDefined(LPCTSTR section, LPCTSTR key);
 	double ReadFloat(LPCTSTR section, LPCTSTR key, double defValue);
 	double ReadFormula(LPCTSTR section, LPCTSTR key, double defValue);