Add notification observer on Mac

SineStriker

2023-12-27 88b5b56b6a67d93208eae3980af2f30da09dd8ae

 src/widgets/widgetwindowagent.cpp

@@ -36,12 +36,10 @@
        w->setAttribute(Qt::WA_DontCreateNativeAncestors);
        w->setAttribute(Qt::WA_NativeWindow);

        if (!d->setup(w, new WidgetItemDelegate())) {
            return false;
        }
        d->setup(w, new WidgetItemDelegate());
        d->hostWidget = w;

#ifdef Q_OS_WINDOWS
#if defined(Q_OS_WINDOWS) && QWINDOWKIT_CONFIG(ENABLE_WINDOWS_SYSTEM_BORDERS)
        d->setupWindows10BorderWorkaround();
#endif
        return true;
@@ -57,9 +55,6 @@
        if (!d->context->setTitleBar(w)) {
            return;
        }
#ifdef Q_OS_MACOS
        d->setupMacOSTitleBar(w);
#endif
        Q_EMIT titleBarWidgetChanged(w);
    }