In debuggin mode, I cannot interact with the GUI when ScheduledExecutorService is running

I have a GUI application which is running fine, however I want to see how everything runs in debugging mode. The GUI has Monster moving in ScheduledExecutorService every 1 second. While the service is running in Debugging Mode, I want to see how User pressing button effects the Application. But, in debugging mode the button does not work, whereas it works when I am running the application normally. Please advise on how I can see user interaction in debuggin mode.

public class MainFrame extends JFrame{

private JLabel monsterLabel = new JLabel("0");
private JLabel statusLabel = new JLabel("Task not completed");
private JButton monsterButton = new JButton("Move Monster");

int monsterPosition = 1;
int playerPosition = 10;

public MainFrame(String title) {
	super(title);
	
	setLayout(new GridBagLayout());
	
	GridBagConstraints gc = new GridBagConstraints();
	
	gc.fill = GridBagConstraints.NONE;
	
	gc.gridx = 0;
	gc.gridy = 0;
	gc.weightx = 1;
	gc.weighty = 1;
	add(monsterLabel, gc);
	
	monsterLabel.setText("Monster position is: " + monsterPosition);
	
	gc.gridx = 0;
	gc.gridy = 1;
	gc.weightx = 1;
	gc.weighty = 1;
	add(statusLabel, gc);
	
	gc.gridx = 0;
	gc.gridy = 2;
	gc.weightx = 1;
	gc.weighty = 1;
	add(monsterButton, gc);
	
    // Button to Move the monster		
	monsterButton.addActionListener(new ActionListener() {			
		@Override
		public void actionPerformed(ActionEvent e) {	
			monsterPosition = monsterPosition + 1;
			setMonsterPosition(monsterPosition);			
		}
	});
	
    // The ScheduledExecutorService runs every 1 second.
	ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
	executor.scheduleAtFixedRate(() -> moveMonster(), 1000L, 1000L, TimeUnit.MILLISECONDS);
	
	setSize(200, 400);
	setDefaultCloseOperation(EXIT_ON_CLOSE);
	setVisible(true);		
	
}

public void setMonsterPosition(int monsterPosition) {
	if(monsterPosition > 1 && monsterPosition < playerPosition) {
		monsterLabel.setText("Monster position is: " + monsterPosition);
	}
	else {
		monsterPosition = 0;
		monsterLabel.setText("Monster has eaten the Player");
	}		
}


public void moveMonster() {
	SwingWorker<Integer, Void> worker = new SwingWorker<>() {

		@Override
		protected Integer doInBackground() throws Exception {
							
			monsterPosition++;								
			
			return monsterPosition;
		}	
		
		@Override
		protected void done() {
			try {
				Integer nextMonsterPosition = get();
				setMonsterPosition(nextMonsterPosition);
			} catch (InterruptedException | ExecutionException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
		}
	};
	worker.execute();
}

}