diff --git a/mainwindow.h b/mainwindow.h
index df47262..3895467 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -27,7 +27,7 @@ public:
 
 public slots:
     void onAppendText(QString, QString suffix = "");
-    void onReplaceLast(QString, QString);
+    void onReplaceLast(QString, QString suffix = "");
     void onShowErrorMessage(QString, QString);
     void onStopStartTimer();
     void onRestartExitTimer();