diff --git a/mainwindow.cpp b/mainwindow.cpp
index 0b8060e..5442d52 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -296,6 +296,11 @@ void MainWindow::about()
     msgBox.exec();
 }
 
+void MainWindow::closeEvent(QCloseEvent * event)
+{
+    m_contentChanged && !closeFile() ? event->ignore() : event->accept();
+}
+
 void MainWindow::setTitle(const QString &title)
 {
     if (title.isEmpty())
diff --git a/mainwindow.h b/mainwindow.h
index 63adf7e..319ad74 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -35,6 +35,9 @@ public slots:
     void keys();
     void about();
 
+protected:
+    void closeEvent(QCloseEvent * event);
+
 private:
 
     void setTitle(const QString &title);