diff --git a/messageviewer/src/viewer/csshelperbase.h b/messageviewer/src/viewer/csshelperbase.h
--- a/messageviewer/src/viewer/csshelperbase.h
+++ b/messageviewer/src/viewer/csshelperbase.h
@@ -81,9 +81,9 @@
     Q_REQUIRED_RESULT QString addEndBlockQuote(int numberBlock) const;
     Q_REQUIRED_RESULT QString addStartBlockQuote(int numberBlock) const;
 
-    virtual Q_REQUIRED_RESULT QString extraScreenCss(const QString &headerFont) const;
-    virtual Q_REQUIRED_RESULT QString extraPrintCss(const QString &headerFont) const;
-    virtual Q_REQUIRED_RESULT QString extraCommonCss(const QString &headerFont) const;
+    Q_REQUIRED_RESULT QString extraScreenCss(const QString &headerFont) const;
+    Q_REQUIRED_RESULT QString extraPrintCss(const QString &headerFont) const;
+    Q_REQUIRED_RESULT QString extraCommonCss(const QString &headerFont) const;
 
     void setHeaderPlugin(const HeaderStylePlugin *headerPlugin);