diff --git a/src/xlsx/xlsxworksheet.h b/src/xlsx/xlsxworksheet.h
index e33a210..5fac3c9 100755
--- a/src/xlsx/xlsxworksheet.h
+++ b/src/xlsx/xlsxworksheet.h
@@ -93,7 +93,7 @@ private:
     bool loadFromXmlFile(QIODevice *device);
     bool loadFromXmlData(const QByteArray &data);
 
-    virtual bool isChartsheet() const;
+    bool isChartsheet() const;
     bool isHidden() const;
     bool isSelected() const;
     void setHidden(bool hidden);