diff --git a/NEWS.md b/NEWS.md
index be87ea26..422bae9c 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 Red Panda C++ Version 1.1.0
   - enhancement: when ctrl+mouse cursor hovered an identifier or header name, use underline to highlight it
+  - enhancement: mark editor as modified, if the editing file is changed by other applications.
+  - enhancement: When the editing files is changed by other applications, only show one notification dialog for each file.
 
 Red Panda C++ Version 1.0.10
   - fix: modify watch doesn't work
diff --git a/RedPandaIDE/mainwindow.cpp b/RedPandaIDE/mainwindow.cpp
index fac394d2..e3faf21b 100644
--- a/RedPandaIDE/mainwindow.cpp
+++ b/RedPandaIDE/mainwindow.cpp
@@ -4151,8 +4151,12 @@ void MainWindow::updateProjectView()
 
 void MainWindow::onFileChanged(const QString &path)
 {
+    if (mFilesChangedNotifying.contains(path))
+        return;
+    mFilesChangedNotifying.insert(path);
     Editor *e = mEditorList->getOpenedEditorByFilename(path);
     if (e) {
+        e->setModified(true);
         if (fileExists(path)) {
             e->activate();
             if (QMessageBox::question(this,tr("File Changed"),
@@ -4178,6 +4182,7 @@ void MainWindow::onFileChanged(const QString &path)
             }
         }
     }
+    mFilesChangedNotifying.remove(path);
 }
 
 void MainWindow::onFilesViewPathChanged()
diff --git a/RedPandaIDE/mainwindow.h b/RedPandaIDE/mainwindow.h
index 7815c84f..95bdd01b 100644
--- a/RedPandaIDE/mainwindow.h
+++ b/RedPandaIDE/mainwindow.h
@@ -740,6 +740,8 @@ private:
     QTcpServer mTcpServer;
     QColor mErrorColor;
 
+    QSet<QString> mFilesChangedNotifying;
+
     //actions for compile issue table
     QAction * mTableIssuesCopyAction;
     QAction * mTableIssuesCopyAllAction;