some changes

DEV/DEV3.1/TP03/Exercise1/GridWindowClosedEvent.java

@@ -0,0 +1,19 @@
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+
+import javax.swing.JOptionPane;
+
+public class GridWindowClosedEvent extends WindowAdapter {
+
+    private GridWindow window;
+
+    public GridWindowClosedEvent(GridWindow window) {
+        this.window = window;
+    }
+    
+    @Override
+    public void windowClosing(WindowEvent event) {
+        int result = JOptionPane.showConfirmDialog(this.window, "Are you sure you want to close this window?", "Close current window", JOptionPane.YES_NO_OPTION);
+        if(result == JOptionPane.YES_OPTION) this.window.dispose();
+    }
+}