--- a/qtbase-everywhere-src/src/plugins/platforms/cocoa/qcocoascreen.h	2021-03-03 12:16:02.000000000 +0800
+++ b/qtbase-everywhere-src/src/plugins/platforms/cocoa/qcocoascreen.h	2021-03-18 09:40:37.000000000 +0800
@@ -44,6 +44,7 @@
 
 #include "qcocoacursor.h"
 
+#include <QtCore/private/qcore_mac_p.h>
 #include <qpa/qplatformintegration.h>
 
 QT_BEGIN_NAMESPACE
@@ -98,6 +99,8 @@
 
     static bool updateScreensIfNeeded();
     static NSArray *s_screenConfigurationBeforeUpdate;
+    static QMacNotificationObserver s_screenParameterObserver;
+    static CGDisplayReconfigurationCallBack s_displayReconfigurationCallBack;
 
     static void add(CGDirectDisplayID displayId);
     QCocoaScreen(CGDirectDisplayID displayId);
--- a/qtbase-everywhere-src/src/plugins/platforms/cocoa/qcocoascreen.mm	2021-03-03 12:16:02.000000000 +0800
+++ b/qtbase-everywhere-src/src/plugins/platforms/cocoa/qcocoascreen.mm	2021-03-18 09:49:55.000000000 +0800
@@ -73,12 +73,14 @@
 }
 
 NSArray *QCocoaScreen::s_screenConfigurationBeforeUpdate = nil;
+QMacNotificationObserver QCocoaScreen::s_screenParameterObserver;
+CGDisplayReconfigurationCallBack QCocoaScreen::s_displayReconfigurationCallBack = nullptr;
 
 void QCocoaScreen::initializeScreens()
 {
     updateScreens();
 
-    CGDisplayRegisterReconfigurationCallback([](CGDirectDisplayID displayId, CGDisplayChangeSummaryFlags flags, void *userInfo) {
+    s_displayReconfigurationCallBack = [](CGDirectDisplayID displayId, CGDisplayChangeSummaryFlags flags, void *userInfo) {
         Q_UNUSED(userInfo);
 
         // Displays are reconfigured in batches, and we want to update our screens
@@ -129,9 +131,11 @@
                 updateScreensIfNeeded();
             }
         }
-    }, nullptr);
+    };
 
-    static QMacNotificationObserver screenParameterObserver(NSApplication.sharedApplication,
+    CGDisplayRegisterReconfigurationCallback(s_displayReconfigurationCallBack, nullptr);
+
+    s_screenParameterObserver = QMacNotificationObserver(NSApplication.sharedApplication,
         NSApplicationDidChangeScreenParametersNotification, [&]() {
             qCDebug(lcQpaScreen) << "Received screen parameter change notification";
             updateScreensIfNeeded(); // As a last resort we update screens here
@@ -239,6 +243,13 @@
     // Remove screens in reverse order to avoid crash in case of multiple screens
     for (QScreen *screen : backwards(QGuiApplication::screens()))
         static_cast<QCocoaScreen*>(screen->handle())->remove();
+
+    // Remove the notification handlers when qApp is released
+    if (s_displayReconfigurationCallBack) {
+        CGDisplayRemoveReconfigurationCallback(s_displayReconfigurationCallBack, nullptr);
+        s_displayReconfigurationCallBack = nullptr;
+    }
+    s_screenParameterObserver.remove();
 }
 
 void QCocoaScreen::remove()