#include <QMainWindow>
#include <QVBoxLayout>
#include <QPushButton>
#include <QWebEngineView>
#include <QEvent>
#include <QApplication>

class Filter : public QObject
{
public:
    using QObject::QObject;

    bool eventFilter(QObject* watched, QEvent* event)
    {
        if (event->type() == QEvent::HideToParent)
        {
            qDebug() << "Hidden";
        }
        return false;
    }
};

int main(int argc, char* argv[])
{
    QApplication app(argc, argv);
    auto win = new QMainWindow();
    auto central = new QWidget(win);
    auto layout = new QVBoxLayout(central);
    auto btn = new QPushButton("Press", central);
    layout->addWidget(btn);

    auto filter = new Filter(win);
    win->installEventFilter(filter);

    QObject::connect(btn, &QPushButton::pressed, win, [&]()
        {
            auto web = new QWebEngineView(central);
            layout->addWidget(web);
        });

    win->show();

    return app.exec();
}

// Call stack showing the hiding of the main window

/*
    Qt6Widgetsd.dll!QWidgetWindowPrivate::setVisible(bool visible) Line 50  C++
    Qt6Guid.dll!QWindow::setVisible(bool visible) Line 655  C++
    Qt6Guid.dll!QWindowPrivate::destroy() Line 2009 C++
    Qt6Guid.dll!QWindow::destroy() Line 1978    C++
    Qt6Widgetsd.dll!QWidgetPrivate::deleteTLSysExtra() Line 1700    C++
    Qt6Widgetsd.dll!QWidget::destroy(bool destroyWindow, bool destroySubWindows) Line 12436 C++
    Qt6Widgetsd.dll!QWidget::setParent(QWidget * parent, QFlags<enum Qt::WindowType> f) Line 10834  C++
    Qt6Widgetsd.dll!QWidget::setParent(QWidget * parent) Line 10631 C++
    Qt6Widgetsd.dll!QLayout::addChildWidget(QWidget * w) Line 864   C++
    Qt6Widgetsd.dll!QLayout::addWidget(QWidget * w) Line 189    C++
    Qt6WebEngineWidgetsd.dll!QWebEngineViewPrivate::widgetChanged(QtWebEngineCore::WebEngineQuickWidget * oldWidget, QtWebEngineCore::WebEngineQuickWidget * newWidget) Line 427    C++
    Qt6WebEngineWidgetsd.dll!QWebEngineViewPrivate::bindPageAndWidget(QWebEnginePagePrivate * pagePrivate, QtWebEngineCore::WebEngineQuickWidget * widget) Line 732 C++
    Qt6WebEngineWidgetsd.dll!QtWebEngineCore::WebEngineQuickWidget::Bind(QtWebEngineCore::WebContentsAdapterClient * client) Line 119   C++
    Qt6WebEngineCored.dll!QtWebEngineCore::RenderWidgetHostViewQtDelegateItem::adapterClientChanged(QtWebEngineCore::WebContentsAdapterClient * client) Line 441    C++
    Qt6WebEngineCored.dll!QtWebEngineCore::WebContentsDelegateQt::RenderViewHostChanged(content::RenderViewHost * __formal, content::RenderViewHost * newHost) Line 313 C++
    Qt6WebEngineCored.dll!QtWebEngineCore::WebContentsAdapter::initialize(content::SiteInstance * site) Line 511    C++
    Qt6WebEngineCored.dll!QtWebEngineCore::WebContentsAdapter::loadDefault() Line 616   C++
    Qt6WebEngineCored.dll!QWebEnginePagePrivate::ensureInitialized() Line 676   C++
    Qt6WebEngineCored.dll!QWebEnginePagePrivate::{ctor}::__l2::<lambda>() Line 117  C++
    Qt6WebEngineCored.dll!QtPrivate::FunctorCall<QtPrivate::IndexesList<>,QtPrivate::List<>,void,void <lambda>(void)>::call(QWebEnginePagePrivate::{ctor}::__l2::void <lambda>(void) & f, void * * arg) Line 129    C++
    Qt6WebEngineCored.dll!QtPrivate::Functor<void <lambda>(void),0>::call<QtPrivate::List<>,void>(QWebEnginePagePrivate::{ctor}::__l2::void <lambda>(void) & f, void * __formal, void * * arg) Line 244 C++
    Qt6WebEngineCored.dll!QtPrivate::QFunctorSlotObject<void <lambda>(void),0,QtPrivate::List<>,void>::impl(int which, QtPrivate::QSlotObjectBase * this_, QObject * r, void * * a, bool * ret) Line 463    C++
    Qt6Cored.dll!QtPrivate::QSlotObjectBase::call(QObject * r, void * * a) Line 374 C++
    Qt6Cored.dll!doActivate<0>(QObject * sender, int signal_index, void * * argv) Line 4036 C++

*/