When trying to close the application changes can be saved, discarded or the exit can be canceled via dialog.

Main.qml

@@ -4,6 +4,7 @@ import QtQuick.Layouts
 import QtQml.Models
 
 Window {
+    property bool discardChangesOnExit: false
     property bool isDataModified: !appUndoStack.isClean
 
     property string titleClean: `${Application.name}`
@@ -16,7 +17,6 @@ Window {
     title: appUndoStack.clean ? titleClean : titleDirty
 
     property int fontSize: 16
-
     property color textColor: "black"
 
     property color wccDarkDark: "#010101"
@@ -49,4 +49,42 @@ Window {
         //     footerText.text = ""
         // }
     }
+
+    onClosing: event => {
+                   if (appUndoStack.clean) {
+                       console.debug("Closing on a clean undo stack.")
+                   } else {
+                       console.debug("Closing on an unclean undo stack!")
+                       if (!window.discardChangesOnExit) {
+                           event.accepted = false
+                           exitOnUnsavedChangesDialog.open()
+                       }
+                   }
+               }
+
+    Dialog {
+        id: exitOnUnsavedChangesDialog
+        title: "Unsaved Changes"
+        modal: false
+        anchors.centerIn: parent
+        width: 300
+        standardButtons: Dialog.Yes | Dialog.Cancel | Dialog.Discard
+
+        contentItem: Label {
+            text: "Do you want save your changes?"
+        }
+
+        onAccepted: {
+            core.saveItems()
+            window.close()
+        }
+
+        onDiscarded: {
+            window.discardChangesOnExit = true
+            window.close()
+        }
+        onRejected: {
+            console.debug("Canceling exit...")
+        }
+    }
 }