Items can be saved via menu action and when exiting application with unclean undo stack.

mainwindow.cpp

@@ -77,7 +77,7 @@ void MainWindow::closeEvent(QCloseEvent* event) {
 
     switch (ret) {
       case QMessageBox::Save:
-        // TODO m_core->saveItems();
+        emit saveItems();
         event->accept();
         break;
       case QMessageBox::Discard:
@@ -233,6 +233,11 @@ void MainWindow::onShowUndoViewToggled(bool checked) {
   }
 }
 
+void MainWindow::saveItems() {
+  showStatusMessage(tr("Invoked 'File|Save'"));
+  m_core->saveItems();
+}
+
 void MainWindow::createActions() {
   // TODO add generic menu actions (file/new, edit/cut, ...)
   createFileActions();
@@ -258,8 +263,7 @@ void MainWindow::createFileActions() {
   m_saveAct = make_unique<QAction>(tr("&Save"), this);
   m_saveAct->setShortcuts(QKeySequence::Save);
   m_saveAct->setStatusTip(tr("Save the document to disk"));
-  // connect(m_saveAct, &QAction::triggered, this, &MainWindow::save);
+  connect(m_saveAct.get(), &QAction::triggered, this, &MainWindow::saveItems);
-  m_saveAct->setEnabled(false);
   ui->menu_File->addAction(m_saveAct.get());
 
   ui->menu_File->addSeparator();

mainwindow.h

@@ -54,6 +54,9 @@ class MainWindow : public QMainWindow {
   void onCleanStateChanged(bool clean);
   void onShowUndoViewToggled(bool checked);
 
+  /// 'File' slots
+  void saveItems();
+
  private:
   Ui::MainWindow* ui;