Problem displaying my main window

[Salazaar]

And in maker.cpp I have to do the same what I was doing with MainWindow:

MainWindow::MainWindow(QMainWindow *parent)
     : QMainWindow(parent)
 {
     ui.setupUi(this);
 
     }
 
      void MainWindow::on_actionAbout_triggered()
            {
 
 
          Dialog dlg( this );
 
 
 
               dlg.exec();
 
 
 
            }

MainWindow::MainWindow(QMainWindow *parent)
     : QMainWindow(parent)
 {
     ui.setupUi(this);
    
     }
   
      void MainWindow::on_actionAbout_triggered()
            {
  
       
          Dialog dlg( this );
   
         
  
               dlg.exec();
  
       
  
            }

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but without implementing slots, right?